Added new level

Added a new prime-sieve level
Fixed id
Attempting to get TravisCI set up to run server tests.
Attempting to get TravisCI set up to run server tests by having it install mongodb.
Merge pull request #1139 from Darredevil/patch-8

Added new level
Updated Danger Minefield icon.
Upgrades to employer's candidate indexing.
Re-added significant trailing whitespace.
Added more names for #53
Migrating language to codeLanguage on systems and components because they conflict with the search system.
Removed some superfluous code
Removed the migration plugins.
Added employer_list and activity tracking.
Final tournament update blurb.
Built a new 'patch' method for CocoModel, which saves only changed values to the server.
Merge pull request #1142 from Xercoy/patch-1

Added more names for #53
Fixed employer list template typo.
Forcing the server to return 200 rather than 304 to requests for the main html file, hopefully fixing some authentication/caching issues.
Having another go at getting travis to run server tests.
Fixed all server-sided tests

NEVER. AGAIN