the function returned 1 millisecond after the required time

See https://github.com/arduino/Arduino/pull/2175

Quoting the original commits from Matthijs Kooijman:

    Enable C++11 support

    This uses the gnu++11 standard, which is C++11 with GNU extensions.
    C++11 should be full compatible with the previously used C++98
    standards, so all pre-existing sketches should continue to work.

    Enable C11 support

    This uses the gnu11 standard, which is C11 with GNU extensions.
    Previously, gnu89 was being used, which is pretty ancient by now. C99
    brings some important improvements, some of which were already available
    and used even without this option. C11 is more recent and brings more
    minor improvements. Most notable feature is the static_assert statement,
    allowing checking invariants at compiletime using the full C
    expressions.

This fix lock-ups on UART errors (for example when disconnecting
and reconnecting RX/TX wires or if the method Serial.begin is
called while another device is already transmitting).

Fixes #4

It seems that

   #include <stdint.h>

is able to undef "min" and "max" previously defined. With this
commit we make sure that they are defined as last.

Fix #10

as in the other Arduino cores

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Signed-off-by: Thibaut VIARD <thibaut.viard@atmel.com>

Interrupt based implementation that works on every pin.

- Renamed Tone.cpp.disabled to Tone.cpp
- Removed commented legacy AVR code from Tone.cpp

This reverts commit bc7115b104428f9bea4fdfa1b6af245085f6f542.

This reverts commit 5024bce531bfeb6f70844f76ea09d7e7de31a067.