It's important to not block a change if you're equal to yourself because,
in general, you're equal to yourself. I'm sure there are some edge cases
in that generalization though.
We are attempting to encourage the pages=layers paradigm; however, this is
not strictly enforced. This commit has lots of bits and bobs but little
actual substance. More to come when I begin work on the exporter.
According to the sparse documentation, custom render engines are the most
future-proof way of customizing the internal blender panels.
Unfortunately, even then, we must do some metaprogramming hacks...
