Handle all git change types in Bitbucket PRs
Created by: felixfbecker
Codeintel on Bitbucket PRs didn't work for many git change types.
This makes it work for all change types. It also splits up the code view specs so there's one per view. There is a unit test per change type for PR code views. It would be nice to have these for each code view though, and there is more potential for unit-testing the small DOM inspection functions. Also adds a lot of comments.
Fixes #3081 (closed) Fixes #3084 (closed)