Switch to github beginning

[Martin Packman]

I am going to stop the tarmac landing bot now and begin the process of
switching our juju repository from launchpad to github.

Note that any branches currently proposed will need their changes
imported into a new git branch in order to land, this can be done once
the git master is up and branched locally. Steps following from the
CONTRIBUTING setup will be something like:

$ cd $GOPATH/src
$ bzr branches launchpad.net/juju-core
* trunk
  wip_feature
$ bzr switch -d launchpad.net/juju-core wip_feature
$ (cd github.com/juju/juju&&git branch)
* master
$ (cd github.com/juju/juju&&git checkout -b wip_feature)
$ (cd launchpad.net/juju-core&&bzr diff -rancestor:co:trunk)|(cd
github.com/juju/juju&&patch  -p0 --merge)

Then resolve any conflicts, stage and commit.

Martin