Create a Matrix_numpy_dense class in Sage

PEOPLE: William Stein, Tom Boothby (remotely; available Monday after 12)

SUMMARY: Add a new file matrix_numpy_dense.pyx to the devel/sage/sage/matrix/ directory that implements Sage matrices that wrap the raw data of a numpy array.

ISSUES:

• Sage matrices are 2-dimensional -- but really could be n-dimensional if the base ring is a tuple-ring say. Interesting.

STATUS: A dream on the horizon.