Use "official" directory for persistent data

ST-andr uses the folder returned by `getApplicationInfo().dataDir` to store persistent data.
However, the "[official](http://developer.android.com/guide/topics/data/data-storage.html#filesInternal)" folder is returned by the API function `getFilesDir()`.

The paths returned by those functions are `/data/data/appname/` and `/data/data/appname/files/` resp.

In most phones the first one works fine. However, in the Razr-i files that are not stored in a subdir, seems to get deleted when the phone is rebooted or an update is installed.

This pull request should correct the problem.

Please test this patch before merging, because:
* I can't test the `moveConfigFiles` part, because the files that should be moved are being deleted when I update and I start from zero anyway.
* I'm not sure that the call of `moveConfigFiles` is early enough.
* I'm new to Android programming - this is my first contribution to an Android project

I hope it works... Constantly re-entering my settings is tiresome :-)