Switch to using build_keys.
Fix for project build tag.
Update the signal handler.
Add ProjectBuilds to the admin.
Change the project_tags parameter to use build_key which makes it clearer.
Update the docstring and remove the comment from the migration.
Merge pull request #48 from bigkevmcd/implement-build-key

Implement build key to help distinguish builds for project builds.
Merge pull request #1 from capomastro/master

Merge forward