Adding tester for buzzer class.
Adding a new class allowing playing notes using a standard buzzer.
Adding pwm class representing a 3 channel pwm device.
Quite ugly for now, need to find a better way abstracting it out and providing nicer interface.

It's currently defined for timers 1 and 2 and supports 3 channels per each. The code is based on the open source NordicSemi library available here...
https://github.com/NordicSemiconductor/nrf51-pwm-library/
Adding the new compilation units to the library.
Removing unused file, also getting rid of commented out code.