Set Oscs as start parameters

If no osc is specified, dummy osc is created with 0 gain.
specify two osc controls in defaults
Add angle conversion utils
Clear rect each frame and trigger controls render
Add controls/fader models and fader view
Add wavetype icons
Increase fader size
Connect audio to controls
Split startVoice into separate function
Rename fader to pot
Add fader model and view to control volume

Also a few usability tweaks, doesn't wait for touchmove before acting
upon the user's click now. Highlights slightly when touching.
Make totalValue a minimum of 1
Add offset angle behaviour for pots with no steps

TODO: Refactor behvaiour for when there *are* steps specified
Add convenient getter to fader model
Rename model attributes, add values object
Add step and value code to pot model
Rename variables to match earlier commit
Add debug log to FaderView
Remove dependency on dual osc controls

Now uses arrays to specify as many or few osc controls and
associated vcas/vcos as desired.
Add padding as data on fader model

... to use in collision detection of fader 'switch'