[Bf-taskforce25] Multires branch

[Nicholas Bishop]

Hi,

I'm wondering about the possibility of switching to the new multires
modifier (from my soc-2008-nicholasbishop branch) for 2.5.

The old multires code had little bits littered all through the code
because a lot of things had to be disabled when multires was enabled.
It'd be nice not to have to port over that old mess for 2.5! This is
no longer a problem with the multires modifier, which is pretty self
contained.

The main problem with the new multires modifier is that it's slower
than the old multires. However, since the storage for displacements is
now nicely separated from the modifier itself, there shouldn't be any
compatibility problems as further changes are made to multires, so I'd
like to see it merged for 2.5.

-Nicholas