Morphing

[pvdz]

The docs don't mention morphing but I'm sure I've seen morphing demos. I think there ought to be section in or next to animation about morphing, as well as details on morphing in the api docs.

[padolsey]

I'm not sure if we should be properly documenting the morphing API until it's 100% tested. I know of some edge cases where it fails, so I hope to work on them before we have it as a real "feature". I'll draft a morphing overview anyway.