Symbols preceded by an underscore are reserved for future introductions
by the c standard/library.

An array index should be of size_t instead of unsigned int.

Internal struct definitions shouldn't be exported by header files.

The validator was used to check that every created tag is validate.
However I now think that validation should take place at a later time,
so it is not mandatory.
Thus developing the validator is now discontinued.

Often it is needed to iterate over the tags. So this was moved to a
macro to reduce code duplication.

Copying a Validator could be useful if multiple html versions are to be
supported. Another use case is a blacklist XSS-Scanner.

A registered tag can be deregistered by calling SH_Validator_deregister.
The data is removed, but the space is not deallocated, if it is not at
the end. This prevents copying data on removal and saves expensive calls
to realloc. Instead the empty space is added to the list of free blocks,
which allows to refill these spaces, if a new tag is being registered.
The space is finally deallocated, if the validator is being deallocated
or the tag written in the last block is removed. In this case, heavy
iteration is performed, as the list of free blocks is not ordered. The
next last tag at that time is determined by iterating over the list of
free blocks until some it is not found.
Note that even if there can be a lot of gaps in between, the Validator
will not allocate more space until all these gaps are refilled when a
new tag is registered, thus new space is only being allocated, if there
is really not enough space left.
Due to the 4 nested loops, there was an issue related to the
72(80)-column rule. It can't be abided without severely impacting the
readability of the code.

Source code regarding tags are exported to validator_tag.c and
validator_tag.h for better separation and integration of new features.

The Validator saves the tags as an array. Now also another information
is added, which slots aren't used currently to spare expensive calls to
realloc. This led to a mere reimplementation of the functions. Tags
can't be deleted by now, but the adding function supports reusing empty
slots. Also the reading functions have to determine, whether a slot can
be read or is empty.
The tests were adjusted, but are buggy, so they should be rewritten in
the future.

Additionaly some annotations for splint were added.

Instead of the trivial structure SH_Error, SH_Status is used. The name
was chosen, because error/status is set independently whether an error
has occurred. Beside the error type, it also contains the associated
errno and an error message. The error message is also printed, when it
is set. Generating error messages with variadic arguments is now also
supported.
There are also macros to check for a set status.

The exception handling was removed for the *_free methods, because they
can't fail predictably during runtime.

Unfortunately the compiler reports, that inside the macro set_status
printf may be called with NULL [printf (NULL)], although, this is
explicitly debarred.

The make process was restructured to create a library. For this libtool
is used to provide both static and dynamic linking. Also header
inclusion guards were introduced, to prevent clients of the library to
include some single file without including others. The types were
exported with forward declarations for better abstraction. When
compiling the library, the macro LIB_SEFHT_COMPILATION is defined and
symbol declarations are exported fully. For compiling the tests this
macro is also defined, as the tests not only tests the API, but also the
internal state, because a lot of errors couldn't be detected otherwise.

The method SH_Text_print just prints the whole string to stdout.

The function SH_Text_get_length returns the length of the text. As the
text also supports being longer than SIZE_MAX, this method can fail on
runtime. If the text is longer then SIZE_MAX, the Text returns SIZE_MAX
and sets error to DOMAIN_ERROR. Note, that due to the implementation,
this is a non trivial function, so don't use it to exhaustively.

The function SH_Text_get_range returns a string begining at start and
ending at end. Note that end specifies the char, that is not returned
anymore. Thus the function implements something similar, as the pythonic
slice syntax (text[start:end]). In opposition to the behaviour there,
calling SH_Text_get_range with start > end is undefined behaviour. If
start == end, the empty string is returned.
If start is out of bounds, NULL is returned and an error is set. If end
is out of bounds, the existent part is returned. Also the length of the
returned string can be set (optionally) to the out parameter length.

The function SH_Text_get_string returns a substring of text beginning at
index and of length offset. If index is out of bounds, NULL is returned
and an error is set. If offset is out of bounds, the existent part is
returned. Also the length of the returned string can be set (optionally)
to the out parameter length.
If the original behaviour of SH_Text_get_string is achieved,
SH_Text_get_string (text, length, error) has to be changed to
SH_Text_get_string (text, 0, SIZE_MAX, length, error). The only
difference will be that the function won't fail, when the text is longer
than SIZE_MAX, because it is told to stop there. A text that is longer
than SIZE_MAX is not possible to be returned, but that wasn't possible
at anytime. Also I don't think handling char[] longer than SIZE_MAX is
possible with the standard C library. Those in this case the text can
only be returned in parts (By now only possible till 2*SIZE_MAX-1 with
calling SH_Text_get_string (text, SIZE_MAX, SIZE_MAX, length, error))
or has to be manipulated using the appropiate SH_Text methods, which are
not implemented yet.

The method SH_Text_get_char returns a single character by a given index.
If the index is out of range, NULL is returned and error->type is set to
VALUE_ERROR.

The (intern) implementation of SH_Text was changed from an array of
char, to a single linked list of arrays of char. This allows an easier
implementation of (further) text manipulation.
The API hasn't changed much, but SH_Text_join can't yield an error
anymore, so it now doesn't support passing an error and returns nothing.

The source has been adapted to splint, which still tells about some
errors, but they are all checked to be false-positives.

A method was added, that returns the generated text.

The constructor SH_Text_new_from_string accepts a string, with that the
text is initialized. This can replace the so far needed two calls
SH_Text_new and SH_Text_append_string.

When writing the test, it was neccessary to simulate an overflow.
Thereby a bug was detected regarding another overflow test. The bug was,
that when SIZE_MAX % CHUNK_SIZE == 0 (which is normally true, if 2^n is
taken as the value for CHUNK_SIZE) there can't be an overflow, so the
test for an overflow fails. Actually there wasn't a neccesity to check
for an overflow, as this could easily be bypassed by just allocating the
requested size instead of the next chunk size, if this would be greater
then SIZE_MAX.

Sometimes a copy is needed.

Fragment serves as a base class for all Fragment types; currently only
NodeFragment exists. It is actually an abstract class, so there is no
constructor.

This renaming is neccessary, as the future Fragmment will be the base
class to all Fragment types.

fixing some bugs detected by splint (-weak) and cppcheck.

When the wrap mode is used, after each tag a newline is started. Also the
html is indented, which can be configured by the parameters indent_base,
indent_base, indent_char. The parameter indent_base specifies the width
the first tag should be indented with, while indent_step specifies the
increment of the indent when switching to a child tag. The character,
that is used for indenting is taken from indent_char. (It could also be
a string longer than a single character).
This aguments can't be set by the user, but are hardcoded (by now).

Fragment can be copied, either recursive (copying also all childs) or
nonrecursive (ignoring the childs, thus the copy has always no childs).
Adding the same element twice in the tree (graph) isn't possible, as
this leads to problems e.g. double free or similars.