Failing test for matching calls to generic methods with derived types
Pending tests marked as explicit for clarity
Potential multiple-enumeration fixed
can now match generic method with derived-type arguments
Test demonstrating an edge case of generic interfaces
Moving [Explicit] test attribute next to [Pending] (so can remove both
  at once)

Adding some tests for matching derived types for generics.
Updating changelog and adding some tests for stubbing generic methods.