attenuation by distance.
Adds:
love.audio.[gs]etDistanceModel(model-identifier)
Source:[gs]etMinVolume(min-volume)
Source:[gs]etMaxVolume(max-volume)
Source:[gs]etDistance(reference, max)
Source:[gs]etRolloffFactor(rolloff)
Valid Distance models:
"none", "inverse", "inverse clamped", "linear", "linear clamped", "exponent",
"exponent clamped"
Suggestion:
Merge Source:setMinVolume, Source:setMinVolume and Source:setVolume. May be
confusing for lovers though.
May have broken platform/msvc2010/love.vcxproj.filters (had to be modified by
hand without really knowing what I am doing).
Also improved memory usage in SpriteBatch. (No need to retain full copy of
sprites in memory. Can read that data back later to save data from OpenGL
context destruction).