The interfaces for inversion in FMatrixC is different
from those in Matrix2|3dC. Charles's suggestion is to
use the implementation from Matrix2|3dC but with the
interface from FMatrixC, so that the faster Matrix2|3dC
ones overload the general FMatrixC one..
Also could add the Inverse(Matrix3dC &result) interface
To see the current mess, look at e.g.