Update project structure to use Android Studio

Android Studio is the IDE that the Android Tools team at Google is actively working on. They are still working on the Eclipse features, but Android Studio is their primary focus right now.  By updating to Android Studio, we now use the Gradle build system.  When using Android Studio, this doesn't really change anything. It does however allow us to build the project from the command line. At some point in the future, I would like to use Travis CI for continuous integration, meaning every commit to Github will automatically be built, and tests will automatically be run.