Blender Git Loki

Fix T44110: Plane track doesn't work when built with scons

For some reason recent change in avoiding non-aligned eigen vectors
was behaving differently for cmake and scons. Made it a bit different
now by storing scalars. This is more robust approach anyway, because
it's not really guaranteed Mat.col() gives a pointer inside data,
depending on column-major vs. row-major storage.

This is to be backported to 2.74 branch.