Fix to allow empty sections of adsr envelopes.
More general interpolation envelopes
Fix in interpolation envelope.
Moved example / manual test code to examples, changes in the sawtooth test.
Started nose-runnable automatic tests.
Python 2 compatibility fix.
Fixes.
Merge branch 'master' of github.com:bluecube/sound_toy

Conflicts:
	waveform_plot.py