Removing AdditionalInfo from CompilationResult since we can't always pass
it into exception thrown

All values in Exception.Data need to be serializable which is not true for
the diagnostics. Removing this property since we can't pass it through.
Fixing unit test
Test for XML documentation errors
- extend the "test" target in our build to use new k-xml-docs-test.shade command

Example output with one syntax error and one invalid reference:
```
info: Target xml-docs-test
warn: Invalid documentation syntax in src\Microsoft.AspNet.Mvc.Core\bin\debug\net45\Microsoft.AspNet.Mvc.Core.xml
warn:   3170: <!-- Badly formed XML comment ignored for member "T:Microsoft.AspNet.Mvc.Rendering.HtmlHelper" -->
warn:   3203: If the object is already an <see cref="!:IDictionaries&lt;string, object&gt;"/> instance, then it is
```