Blender Git Loki

Mathutils: add a Matrix.LocRotScale constructor for combining channels.

Combining location, rotation and scale channels into a matrix is
a standard task, so while it is easily accomplished by constructing
and multiplying 3 matrices, having a standard utility allows for
more clear code.

The new constructor builds a 4x4 matrix from separate location,
rotation and scale values. Rotation can be represented as a 3x3
Matrix, Quaternion or Euler value, while the other two inputs
are vectors. Unneeded inputs can be replaced with None.

Differential Revision: https://developer.blender.org/D11264