Blender Git Loki

Freestyle: minor speedup by omitting unnecessary transform matrix operations in the file loader.

Previously the imported mesh data were transformed by a local-to-world projection matrix
through NodeTransform. Now that the file loader assumes the imported mesh data already
in the camera coordinate system, an indentity matrix was supplied to NodeTransform.
The present commit avoids this redundant matrix operation by using NodeGroup instead of
NodeTransform, recalling the latter is a subclass of the former with extra matrix computations.