Update glyphs visualization

This introduces bug fixes to all glyph based visualization (namely ODF and tensors). The main one being that when you dropped an image alone with a non identity orientation, slicing was corrupted. Now it's corrected.

Opacity has also been added to vector and SH visualization. We'll have to see if we keep Mike's branch or add this one on top of it.
When you do the refactoring, can you take this and put it at a higher level, as it's duplicate code? Also perhaps swap around how we walk the matrix - at the current size it probably doesn't matter (unless the cache is really contested) but it couldn't hurt.