build: Update karma and switch from PhantomJS to Chrome

* karma from 0.12.23 to 0.12.24
* karma-chrome-launcher from 0.1.4 to 0.1.5
* karma-qunit from 0.1.3 o 0.1.4
* qunitjs 1.14.0 to 1.15.0

Not testing with Firefox yet as that doesn't pass (yet).

Change-Id: Ia0ec7b8a2a0aab22c144c82b87ac79a25ad550ae