Add a script to install support library from android's m2 repository.

Since gradle users don't use the directory `extras/android/support/v4/android-support-v4.jar` (they use `extras/android/m2repository/com/android/support/support-v4/19.0.0/support-v4-19.0.0.jar` instead) the `install-support-jar` script will fail. I just duplicated it and changed the path to the other location.