Adds widget launching functionality on Android

Widgets can be launched using the AppLaucher API by specifying the ID
of the installed widget.

Removes issue with quotes on AppLauncher's testbed page.

Jira issue: WP-874
Cleans up code. Removes untidy whitespace.

Jira issue: WP-874
Merge pull request #533 from mlasak/WP-874

Adds widget launching functionality on Android