Log Message:
Import topgit-0.7 as devel/topgit.

TopGit aims to make handling of large amount of interdependent topic
branches easier.  In fact, it is designed especially for the case when
you maintain a queue of third-party patches on top of another (perhaps
Git-controlled) project and want to easily organize, maintain and
submit them.  TopGit achieves that by keeping a separate topic branch
for each patch and providing few tools to maintain the branches.