Better DVCS support via post-commit workflow

by Eduardo Felipe Castegnaro for Review Board

Create an algorithm to detect token renaming on diffs and add an interface option for collapsing rename changes, simplifying the review process. Add branch tracking in a review providing a way to pull newer changes in the branch from the repository into the review via the web UI; detect if the changes were already merged into the trunk and allowing the review of a patch as a whole or as a series of individual commits, making Review Board better fit a modern post-commit review workflow.