Add LocaleList support to content.res.Resources.

Also remove the adjustLocales() method, since it's no longer possible
to create non-adjusted Locale objects using the public API.

The implementation is still in progress: currently only the first
locale in the list is passed down to the native code.

(Also fix the order of imports based on Android style.)

Change-Id: I325d7a2c0d86a9bf5cd202081f0b02299660364a