*BROKEN* Snapshot as-is, though.

Added cubemap support and it is likely working...but also made a change for handlinge iChannel[0] -> iChannel0 to match the sampler syntax change that shadertoy.com made.  That is breaking things.

Exception in thread "Thread-670" java.lang.IllegalArgumentException: No matching method found: glUniform1

is the current situation.  Will figure it out after a good night's sleep.
Fix issue 21.  Add support for cubemap textures and adjust API for iChannel[N] -> iChannelN change.  Proved that it works for me for Simon Green's example https://www.shadertoy.com/view/Xdf3zM although I had to use iOvertoneVolume instead of the fft data.
Adjust iChannel0..3 api.