Picking GitGraph files from Blueprints repo.
Don't forget the test code.
Merge GitGraph Java source files from Tinkerpop Blueprints repo (git://github.com/tinkerpop/blueprints.git).
Put GitGraph source files in their own subdir.
Put GitGraph source files in their own subdir.
Merge pull request #4 from jimwhite/master

Recover GitGraph Java source files lost in move from Blueprints.