CYB-324 - Gallery Performance: refactor API to return results faster

https://jira.ets.berkeley.edu/jira/browse/CYB-324
CYB-346 - Gallery Performance: Refactor front-end for new API changes

https://jira.ets.berkeley.edu/jira/browse/CYB-346
CYB-346 - Gallery Performance - fix tests
https://jira.ets.berkeley.edu/jira/browse/CYB-346
Merge pull request #206 from christianv/CYB-346

CYB-346 - Gallery Performance: Refactor front-end for new API changes
Accelerate the Gallery API

* Pull out data in raw SQL, massage in Ruby to get the format needed by the API
* uses new hash_refinement.rb, removes several methods from array_refinement.rb

Spec failures kept popping up on unrelated (very old) code, fixed those as well.  Those mostly consisted of leaky state.

* CYB-324 Gallery Performance: refactor API to return results faster
* CYB-338 Add API endpoint for single gallery item
* CYB-339 Remove comments json from gallery index API endpoint