Merge: Clean up Android and Linux app.nit libraries

The prefix in `linux_data_store` and `android_data_store` is no longer needed.

Importing only `dalvik` from an Android module makes it compatible with both implementations: the newer nit_activity and the older native_app_glue still used by games.

Pull-Request: #1325
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>