Copy one matrix to another, resizing if required
void mtx_copy<M, N>( M& m, const N& n );
A reference to a target object of type M that supports the imtx<T> interface.
A reference to a source object of type N that supports the imtx<T> interface.
This template function copies one matrix to another, resizing the target matrix if required.
Both matrices must support the imtx<T> interface. The matrixes do not need to be of the same type, but they should each have the same item type T.