SHFB should support reflection.org files as documentation sources

[EWSoftware]

Moved from CodePlex
Originally submitted by mmenningen

The reflection.org files (API descriptions) sometimes have to be generated by tools other than the MRefBuilder. It should be possible to directly include reflection.org as documentation sources. reflection.org should also be supported to resolve references, if possible.

Updated 01/25/2015 - EFW - Reflection files cannot be used to resolve references. That would require parsing them and building the equivalent set of information obtained from an assembly which is just not feasible. Bypassing MRefBuilder and using output generated by some other tool should be possible though.

[EWSoftware]

Merged with #898