Add Karma unit tests

Added Karma Unit tests for AngularJS controllers/ and services/

Moved existing tests into test/mocha/

Karma will create a test/coverage/ report folder which is .gitignored

Karma configs are kept in a separate file rather than in gruntfile.js

Karma is set to use PhantomJS but is easily changed to Chrome (or other browsers via config)

Karma will run with server start ("grunt") and run when watched files are changed plus also manually using "grunt karma:unit"