Emit pinned/tripleslash reference comments of signatures

Fixes #501
Emit pinned/tripleslash reference comments of interfaces

Fixes #501
Emit pinned/tripleslash reference comments of ambient declarations

Fixes #501
Emit pinned/tripleslash reference comments of elided module declaration

Fixes #501
Merge pull request #516 from Microsoft/pinnedComments

Emit pinned or ///<reference> tag comments for signatures, ambient declaraitons and interfaces