Run QUnit tests using Karma runner

This includes several changes:
 - custom home-brew test runner is removed in favour of
   using Karma runner.
 - more modern versions of jquery and qunit are used, and
   installed using npm, instead of including copies of
   libs in the git repo. jquery is only used to have access
   to $.extend, and it also works in jquery 3 without changes
   to our code!
 - QUnit-parameterize has no public version (neither official
   npm package neither custom in-house fork used so far) that
   works with QUnit 2, so it has been dropped too. Changes to
   tests are not significant due to small size of the library.
   All previously tested behaviour is still tested.
 - RequireJS, only used for tests, is no longer used,
   Karma config specifies dependencies for tests to run.
 - QUnit tests are run as part of npm test. Bash build script
   is removed.