Inspector relations tab now shows the units involved in the relation error
Remove killing xvfb since it can be shared.
Added unit tests for relation methods in the relation viewlet
Merge pull request #42 from mitechie/test-merge-singularity

- Currently if a test and a merge (landing) job are running on Jenkins they interfere and will not pass due to no fault of the dev.
- This is due to one of them killing the xvfb process running while the other is sharing it.
- After a pre-imp with Benji it was decided there's no harm in leaving it running currently and it's the most expedient way to getting a safer CI process into place. 

Notes:

We may want to revisit this, as noted in the docs in line, if we want to do things like snapshot images in case of a failing test, etc. We can then make the xvfb port configurable as part of that work.

QA
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Note that below we have failed test and merge runs. I've updated the branch to remove the failing test and it's ready for review.
Added additional comments for clarity
Merge pull request #43 from hatched/relation-unit-errors

This branch adds the units in error to the relation tab in the inspector. There are only unit tests because the timings are unreliable for a purely js test and would require a settimeout/polling. It would be better tested using selenium.

To QA:
deploy mysql & wordpress
relate them
scale one to 100 units with the simulator on and then switch to the relations tab
once there is a unit in relation error it will show up in the list.
scale it down to 1 unit and switch back to the relations tab quickly you should notice it dissappear.