Adding new chrome `identity` permission.
Triggering the authFlow.
Last.fm controller now emits an event when auth is "successful".
Last.fm conditional UI:
- login link if not authenticated
- last.fm username and scrobbling checkbox activated otherwise

Updated translations.
Made use of placeholders to display the username in a translated string.
Deactivated JSHint for a good reason.
Merge pull request #48 from oncletom/fix-48

Last.fm OAuth flow is broken