Configured Karma for coverage reporting. Added 'coverage' target to test/build.xml.

Fixes #103
Added Sencha Touch 2.2.1 and Ext JS 4.2.1 to the automated test suite.

Add both as options in the manual test runner (along with a tweak to handle CDN path differences for newer Ext JS releases)
Added Karma configuration files for both framework versions.
Added both to 'test' and 'coverage' targets in the test/build.xml ant script.

Fixes #104
Fixes #105