[Android] Remove an unnecessary method override from GameListActivity.java. We don't actually do anything different from the default behavior of this method, so we don't need to explicitly define it.

This method is intended to be used for modifying the contents of a menu before displaying it. We don't really have a need for this, since it doesn't need to be modified.
[Android] Explicitly specify the allowBackup attribute in the manifest.

It's considered good practice to specify it, so why not?

Basically it allows the application to be backed up or restored via ADB.
[Android] Add correct density-sized images of the navigation drawer icon. Now all icons are density-specific.
[Android] Add xxhdpi versions of the file icon and the folder icon used in the folder browser.
[Android] Externalize how the formatting is used in the file size string, the file clicked string, and the current dir string.