Map remote branches to local branches

When creating a new user or reinstalling, map the remote branches on
GitHub to local tracking branches automatically, except for "develop"
and "master" (which remain tracked to dreamwidth). This allows people to
jump straight back into working on a branch in progress without needing
to worry about setting up their branches first.
Merge pull request #27 from Sophira/map-remote-branches

Map remote branches to local branches
Leave /dreamhack/var/maintain.d/.placeholder alone

For ages I've tried to work out why this file was mysteriously
disappearing and subsequently causing git to delete the parent
directory, messing up its permissions in the process. Turns out it was
getting deleted by maintain-dreamhacks after it assumed it was a file to
take action on.

This change tells maintain-dreamhacks to leave the file alone - not to
take action on it and not to delete it.
Merge pull request #28 from Sophira/keep-placeholder

Leave /dreamhack/var/maintain.d/.placeholder alone