[Bf-codereview] MDef BVH Support (issue 4529048)

[brechtvanlommel at gmail.com]

The function meshdeform_tri_intersect has a big epsilon to ensure no
rays slip through (float precision issues). Actually my main concern
with this patch is that the BVH epsilon is possibly too low. It should
be tested to give the same results on geometry with mixed small/big
faces, faces close to and nearly overlapping the cage boundary.

http://codereview.appspot.com/4529048/