Don't depend on import side-effects.
Put the pushmanager's name in the irc message.
Prepare for 0.2.1
Merge from asottile/pushmaster_in_message

Clean up imports.
Merge pull request #63 from asottile/pushmaster_in_message

IRC messages from pushmaster should be addressed with the pushmaster.
Add CHANGELOG
Update pushes.html
Merge pull request #67 from asottile/relevant_bbs

Update pushes.html
Keep local versions of git repos in pushmanager

Add method to clone or update a git repository
Allow multiple task type in GitQueue

Instead of just verifying that branches exist, Git now also has the option to
test pickmes. So that we can queue this, GitQueue needs to be changed to take
a GitQueueTask which can be one of:

- VERIFY_BRANCH: check that a branch can be found and is not a duplicate
- TEST_PICKME_CONFLICT: check which (if any) branches also pickme'd for the
    same push cause merge conflicts with this branch

This also renames the update_request methods in core.git to verify_branch,
so the tests need to be updated appropriately.
Create context managers for branching and merging

To handle setup/teardown of test branch creation and testing whether merges
break, create two context managers.
Test pickmed branches for conflicts, save results

Create method queued by the pickme servlet that checks that pickme against other
pickmes in the same push. Tag any pickes that fail to merge on top as conflicts
Introduce GitException

In order to more obviously pass Git output to places it's needed (such as in
pickme_conflict for reporting which files conflict) create an Exception with
three git fields for return code, git stdout and git stderr
Display conflict text on website, add tag colours

Encode the 'conflicts' database field into the JSON representation of a request.
Set colours for the conflict-master and conflict-pickme tags
Style the Conflicts section on the request detail div
Requeue pickmes that are conflicted against

If a pickme is added that conflicts with other pickmes, requeue those pickmes so
that they also get tags and details attached to them.
Send email when conflicts are detected
Switch from Threading to Multiprocess

Avoid global locking if git takes too long
Add simple tests for GitContextManagers
Add XMPP messages
Make xmpp server configurable