Merge pull request #500 from diizy/stable-0.4

Piano widget: fix velocity, Opulenz: increase volume
Start wavetable synth
WTSynth files
Changes
Changes... now it seems to work
Updates, fixes etc
Fixed multiplier weirdness
Move stream buffers to the synth object
Fix mixing / modulation behaviour, add some  more buffer safeguards
Correct phase mod algo (add below-bounds check)
Graphics
Add some mixer locks
Revert earlier
Copy wavegraphs to synthobject at note start, prevent hangups if wave edited while playing
Added simple mix envelope
Adjust previous
Add hold knob
fix previous