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.

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.

The methods
- SH_Fragment_get_child (by index)
- SH_Fragment_is_child (non recursive) and
- SH_Fragment_is_descendant (recursive)
were added.

A Fragment can contain childs. When building the html, the childs html
is generated where appropiate.

SH_Text_append_string can be used to append a string to the text,
SH_Text_append_text can be used to append another text to the text.
SH_Text_join is a wrapper for SH_Text_append_text, but also frees the
second text, thus joining the texts to a single one.

A Fragment can output it's html. If there is an error the method aborts
and returns NULL.

Changing sefht_validator_test so that no memory leaks occur.

The space a Text has for saving the string is allocated in chunks. To
request additional space SH_Text_enlarge is called. If the requestad
size fits inside the already allocated space or is even smaller than the
current size, nothing is done. Otherwise a multiple of chunk size is
allocated beeing equal or greater than the requested size. The chunk
size can be changed by changing the macro CHUNK_SIZE in src/text.h. The
default is 64.
This adjustment is done automatically when a string is added.

Check in tests whether error really was written, by setting it to
undefined before each call.

This is a data type to deal with frequently appending to a string.

When a tag is made known to the Validator, which it already knows, the
old id is returned and nothing is added.
As this has to be checked by iterating over all known tags, a new helper
function is written for both SH_Validator_check_tag and
SH_Validator_register_tag: SH_Validator_get_tag.

Because we want also to test this function, we have to include
validator.c in the test file and override the static keyword by an empty
macro. It isn't possible any more to check for correct overflowdetection
by setting the index to UINT_MAX, because it will be iterated over all
data, thus raising an SIGSEGV when doing so. This is solved by filling
garbage unil UINT_MAX is really reached. As there would be an timeout
and it would fill RAM with around 40 GB of garbage, UINT_MAX is
overriden prior to inclusion of validator.c .

Validator serves as an syntax checker, i. e. it can be requested whether
a tag is allowed.

Tests are done using check, allowing to integrate the tests into the
Autotools.
Methods that are part of another unit, but are called in this unit
aren't tested as this would interfere with the idea of unittests. This
also applies for purely wrapper functions, where a call is passed to
another unit.