Handle symbols that are defined in multiple places.

[JoshVarty]

For example in C# there are partial methods and partial classes that will be defined in multiple places. Currently, we just (randomly) choose one of the definitions and link to it.

This is bug number two in #57

[AmadeusW]

As per MSDN: Partial classes and methods a partial method can have one partial definition and one partial implementation. This simplifies the problem such that we need to link only to the implementation (from the user's point of view, it's the implementation that matters.) Thoughts?

[JoshVarty]

That's true for partial methods, but partial classes may have multiple implementations.

For example: http://source.roslyn.codeplex.com/Microsoft.CodeAnalysis.CSharp/a.html#9a30560b92496a20

[AmadeusW]

You're right, we can't simplify this like that.