Blender Git Loki

Store root orientation matrix in strand curves as well as caches.

This matrix is needed to create a stable and smooth coordinate system
along the strands, for things such as bending forces and child hair
deformation. The base matrix is defined on the "scalp" mesh and should
be stable wrt. deformation and animation of the mesh. For any point on
the strand a matrix is then calculated using parallel transport, i.e.
by rotating the base matrix successively along each curve corner.