Math.NET Numerics Matrix formatting (implements #20)

Note that this PR includes the patch from @dcharbon, which to my understanding actually requires to be integrated with Deedle first. This would need to be coordinated. Alternatively I can drop commits 50563ec and 5812da0 from the PR, so it works independently - just let me know what works better.

See #20

In LaTeX uses the amsmath/bmatrix environment.

In HTML currently uses tables just like deedle, but I agree that it would be nice to use MathJax here with the same LaTeX environment as well. I'll add that later today.