rubex typed memoryviews

[dsisnero]

cython uses typed memoryviews for direct access to underlying c objects that implement a buffer protocol. Add something similar so that we can declare memoryviews on numo::narray , narray, and other objects and have direct pointer views of these objects

[v0dro]

This would be a good feature. If you have any thoughts on how it can look in a Ruby-esque manner, please post them here so its helpful when we implement this.