Remove compatibility library dependancy

This removes the need to include the ~350k android-support-v4.jar library. The primary use case for these changes will be for developers targeting Android 3.1 and later where all of the functionality provided by the library is already in the OS.

The use of these changes will need to be a strategic decision as much as a technical one. I'm creating a pull request so others can find the changes and use them if they want to, but I suspect you'll want the number of pre-3.1 android devices to fall further before integrating this into the main release.