Make the phone build smoother

This consists of two changes:
- Check in some more autogenerated files to be ignored, to make the git workflow smoother
- Removed the maven build files temporarily to avoid confusion

And updated the README to highlight the fact that the project is designed to be
built using the Android Development Studio.
Merge branch 'ticket_3' of https://github.com/shankari/e-mission-phone into ticket_3