Blender Git Loki

Object transform evaluation is now done in new-depsgraph-driven callbacks instead of ubereval

* The ubereval is still lurking around for handling proxy cruft

* I've implemented a stripped-down version of the parenting code for
use here (notably, without the slow parenting, and originmat support).
The old/full version did a bit too much for us to be able to keep the
old code running while we worked on the new version too, without making
the code too messy.

Later on, when we work out the geometry handling a bit more, we may need
to replace the parent-matrix finding code it uses too (i.e. to make it
grab data from context instead - especially in cases where it hunts for
this info itself currently).