Second Release - adds a timer for SAMD21

Has M0 Timer code to blink D13 independently of the main program.

To be used (possibly) as a timer for the main loop (oscilloscope)
measurement. To make the loop more effcient, though experiment.

What's Changed

• Release/0.1.1 pre alpha by @wa1tnr in #3

Full Changelog: 0.1.0-pre-alpha...0.1.1-pre-alpha