
try:
  from mathutils import Matrix, Vector
except ImportError:
  # We don't have mathutils. Make some very basic replacements.
  class Vector(tuple):
    def __repr__(self):
      return "Vector({})".format(super(Vector, self).__repr__())
  class Matrix(tuple):
    def transposed(self):
      cols = [[self[j][i] for j in range(len(self))] for i in range(len(self))]
      return Matrix(cols)
    def __repr__(self):
      return "Matrix({})".format(super(Matrix, self).__repr__())

Add previously-missed placeholder Vector/Matrix code
Add previously-missed placeholder Vector/Matrix code

This lets us use the read.py script without having to import the Blender
module, at the moment. Importing should probably be kept separate from
reading into blender, but it's convenient to share math structures if
possible.
