simple solution for spatialization with SC, without SSR. segments fade in and pan from the peer's position (random) to the centre. in need of refactoring.
towards more flexible spatilization with SC, without SSR.

Merge branch 'sc_spatialization'

Conflicts:
	orchestra.py
recovered flat envelope for normal non-looped playback, which was unintentionally (?) changed to fade-out when looping was introduced in 7dd6552e (the fade-out was probably only supposed to apply for looped playback with \loop)
added SC mode for rear-to-front panning with 4 channels (no left-right panning)
added 6-channel rear-to-front mode
SC optimization
added -profile option to visualizers. also replaced sys.exit() with a cleaner shutdown.
further possibilities for profiling visualizers
fixed bug in visualizer.py causing argument errors
refactoring
fixed bug in geo/locations.py
minor refactoring
adding new geopgraphical experiment: "heat map", with dots for each unique location
fixed error-output bug in simple_osc_receiver.py
heat map shows current activity
heat map: stroked instead of filled circles
heat map: optimized, and fixed bug
heat map: pulsing connected to segment playback. new peers properly added to history layer.
added simple particles emitter peers