equivalence graph visualization controller and resources.

Add controller to provide data for and javascript and template to
produce  d3.js-based equivalence graph visualization.
Add contributions section
Merge pull request #233 from atlasapi/equiv-viz

equivalence graph visualization controller and resources.
Merge in MBST-3616 to use disable keys feature with newer version of master
Make InvalidAPIKeyException a runtime exception
Merge mbst-4171-api-key-disabling-reviewed