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