fw0.2.0

Firmware update only with the following changes:

• Fixed a bug where waveforms would produce garbage output noticeable only under certain update frequency settings because the wrong buffer was being specified as the last buffer.
• Added normalized_phase_shift to sine and trapezoid players
• Added duty_cycle to trapezoid player
• Updated python and bonsai interfaces.

To install the latest firmware, have a look at the instructions in the README.