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
"Initializes a Roslyn-based ..." (add "a" and the hyphen)
or, I believe our standard words would be `Initializes a new instance of the <see cref="RoslynCompilationService"/> class.`.