Add vagrant for development on other OSes

* Add Vagrantfile for specifying box and networking
* Add vagrant-provision.sh for fleshing out the VM
* Add info on vagrant to HACKING
* Add .vagrant to .gitignore
Update the ci docs with the new process and setup
Merge pull request #44 from mitechie/ci-docs-update

This is a pure docs update with the goal of helping other devs be able to walk into the CI system and find their way around. It provides some debugging tips and descriptions of the moving parts.

I've left the older instructions and noted them as bitrotten per the old Hacking docs. Those notes deal with starting up and dealing with a live Juju environment which CI does not use. Those notes might prove useful in bringing that back up at some point in the future.
Tests now run in vagrant; docs updated per reviews.
Added util for rendering viewlets and added service-relation viewlet tests
Added missing dependency in viewlet relations module
Merge pull request #41 from makyo/vagrant

* Add Vagrantfile for specifying box and networking
* Add vagrant-provision.sh for fleshing out the VM
* Add info on vagrant to HACKING
* Add .vagrant to .gitignore
Merge pull request #45 from hatched/viewlet-test-scaffold