Relation refactor

Add in the concept of relation collections to store multiple relations between two services in a single object, allowing for a menu to display the individual relations separately.

To QA:

* run make devel, visit 0.0.0.0:8888/:flags:/relationCollections
* add hadoop, add hadoop again as hadoop1, add mysql, add mediawiki
* relate mysql and mediawiki; should look fine; should be able to delete relation by clicking on relation indicator (currently a circle)
* relate hadoop and hadoop1 twice, in multiple ways; should only see one line (right click on indicator, inspect element, should only see one .rel-group); should be able to delete *twice* (deleting specific relations coming soon with menu, but for now, deletes in order created).
* no errors on console with general QA
* no errors in tests.