Implement a Cobertura coverage provider

[mispencer]

It would be nice to be able to render coverage from Cobertura files.

I have a simple implementation that could be built on for this.

[napsta32]

I wonder if this will ever be implemented. With cobertura.xml or jacoco.xml support, most of the programming languages
code coverage should be supported.

I wonder if a parser could be implemented for this to work (instead of using a different coverage provider).

[mispencer]

This commit is the implementation I referenced earlier.