switcher.py: Repond directly to keypress, also send vol up/down
soundserver: Fix per-volume panning/volume, make OSC controllable

One cannot actually set properties on a NodeProxy source, but
just replacing it seems to work well.
soundserver: Tweak volume of events compared to sequences
soundserver: Make MyPaint grainsynth less heavy, and move code to score.sc
switcher.py: Update IP config, correct swapped volume/pan values
soundserver: Add a couple of different synths to score
midicontroller.py: For controlling performance using AKAI LDP-8
midicontroller.py: Fix pan mapping to [-1.0,1.0]