Make it working with gradle android 0.9.0 plugin

Summary:
Android team recently released gradle android 0.9.0. I had hoped that
they added builtin support for robolectric. However, couldn't make it
working with the examples. Maybe I am missing something?

This plugin works with 0.8.+, but not 0.9.0 due to some breaking changes.
See release note at http://tools.android.com/tech-docs/new-build-system

Here we add 0.9.0 support. Tested it with both: 0.8.x -> 0.9.0
- Rename instrumentTestCompile to androidTestCompile
- Rename src/test/java -> src/androidTest/java
- Install this plugin locally
- Run gradle clean test with local plugin

Please Note: The example project is broken in many ways. I could not get
it working with neither 0.8.+ nor 0.9.0, neither gradle 1.9 nor 1.10.
The error is: http://pastebin.com/Q8iFDBGn. Did checked different
solutions, including android issue reports. I would suggest that fixing
the example is future work, as it seems more related with flavor support.