Add test cases for CommunicationsBridge

Test and related files need to be in the wikipedia/ project
than the wikipedia-it project, since the test cases are run
with the context of the wikipedia/ project.

Also added a 'injectScript' feature to the bridge that lets
javascript be loaded dynamically at runtime.

Change-Id: Ibe0ef8f5e6efc13f56960e10b7e0de6fa9f461db