Propogate additional compilation data from RoslynCompilationService

* Update CompilationFailedException to include path of file being compiled
* Pass in path being compiled to Rolsyn.
* Adding doc comments for compilation pieces

Fixes #869
We were passing in an empty string to this method prior to this, so the change was simply culling the argument out. 
If we were to do this correctly, we'd end up having to cache the compiled content along with the generated type in our results. Seeing that you'd have these strings hanging around in memory with nearly no use, I don't see why we need to make this work.