Update to VolumeRenderer
Added bounding volume edge rendering
Update to VolumeRenderer
Reusing same texture for rayEntrance and accumulation of density
Updated libRigid3D.a
Update to GpuSmokeSim3D
Rendering static density field
Fixed volume rendering bug
No more density values showing up at the top of bounding cube,
or weird circular artifacts from nadar views.

Just needed to set WRAP_R modes for the 3D textures
Update to GpuSmokeSim3D
Advecting density field upwards works
Fixed merge conflict