Added Locale Service. Minor Controller Refactoring.

Hi there!

I started extracting some "buisiness" logic into a seperate provider/service. My goal, also in preparation for angular 2.0 some day, is to have as much of non binding logic to fit in services. So the migration won't be to much of a pain one day.

I started with this small chunk because it was just easy to extract. So that the monster SyncthingController can shrink in size over time.

Regards,
Dennis
I'll trust your judgement here, Angular isn't my strong suite. :)