fix(Makefile): enable targets to work for non-Vagrant

Adds DEIS_HOSTS, which is set automatically or can be overridden
for non-Vagrant platforms. This is used by ssh_all to determine
which hosts to SSH into - previously, we used `vagrant ssh`,
which obviously only works on Vagrant.

This also updates all the Makefiles to use fleet as appropriate,
and to pull / build / etc. on all DEIS_HOSTS.

TESTING: try the various make commands on Vagrant and Rackspace/EC2

replaces #998
closes #811
Merge pull request #1026 from deis/deis_hosts

fix(Makefile): enable targets to work for non-Vagrant
feat(router): route deis.domain to controller

Forwards requests to deis.domain to the controller.

TESTING: rebuild the router and controller with this change:

    $ make -C router build restart
    $ make -C controller build restart

Test that deis.domain routes to the controller and that other
requests to the domain route to the app. Also, send several requests
to the API and be sure that nothing broke related to auth because
of the proxying of requests.

The integration tests were updated to test the controller and the app
routing, so you can also `cd test && bundle exec rake`.

Also, try creating an app with the name of 'deis' - it should be
rejected.

replaces #974
part of #535