Added LLVOVolume::isVisible()
Avatar VBO now uses stream type under all scenarios. Todo: Perf test.
Added other misc render-related tweaks that looked safe.
Update 1: Align Planar Textures.
Update 2: Copy/Paste buttons for texture params now work.
Sorry about another two-in-one patch, but y'can't really change one without the other on this.
Signed-off-by: Beeks <HgDelirium@gmail.com>