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>

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>

For some reason the blocking read from the original USB-CDC driver
is not reliable. As a workaround it has been reimplemented using a
polling loop with the non-blocking read function that, instead, is
much more reliable.

Eventually the USB_Read_blocking(..) in cdc_enumerate.c will be fixed
in the future.

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.

Conflicts:
	hardware/arduino/sam/platform.txt

Conflicts:
	hardware/arduino/samd/cores/arduino/wiring_analog.c