Blender Git Loki

Move bevel list and path from Curve to Object datablock

I know this is not so much nice to have this guys hanging
around in a general Object datablock and ideally they better
be wrapped around into a structure like DerivedMesh or
something like this. But this is pure runtime only stuff and
we could re-wrap them around later.

Main purpose of this is making curves more thread safe,
so no separate threads will ever start freeing the same path
or the same bevel list.

It also makes sense because path and bevel shall include
deformation coming from modifiers which are applying on
pre-tesselation point and different objects could have
different set of modifiers. This used to be really confusing
in the past and now dtaa which depends on object is stored
in an object, making things clear for understanding even.

This doesn't make curve code fully thread-safe due to
pre-tesselation modifiers still modifies actual nurbs and
lock is still needed in makeDispListsCurveTypes, but this
change makes usage of paths safe for threading.

Once modifiers will stop modifying actual nurbs, curves
will be fully safe for threading.