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
`object` has a very long description of its `ToString()` method, most of which isn't relevant here.  Instead say something generic in a `<summary/>` and add `<remarks/>` that (unlike those in `object`), are relevant here such as `<remarks>Returns same value as <see cref="Message"/></remarks>.`.