1. Added Google Play Services Library to build path.
2. Created fragment for checking if Google Play Services is currently
installed on device.
3. Created ActivityRecognitionService for handling changes in user
activity.
Revert "1. Added Google Play Services Library to build path. 2. Created fragment for checking if Google Play Services is currently installed on device. 3. Created ActivityRecognitionService for handling changes in user activity."

This reverts commit 320f3269eac7dc5aac159d7fcb63ecf2b2d4c4dc.
1. Added Google Play Services Library to build path.
1. Fixed Google Play Services build path issue.
1. Created fragment for checking that Google Play Services is installed
and enabled.
2. Created service for handling changes in user activity.
3. Made minor changes to comments and tags in existing services.
1. Updated onActivityResult method in GooglePlayServicesFragment for
clarity.
1. Implemented ActivityRecognitionService.