New Feature: Following Flow. Issue #95.

New Feature: Following Flow. Issue #95. Following: browse followed users. Profile: checkout a specific followed user with picture, description and tracks. New wrapped API-calls in SCApiService. Also a new getNextPage method that lets the controller keep track of which items that shall be fetched next. I believe the new getNextPage method should be implemented to all controllers, cause the one that is being used right now sometimes  'freezes' because it has the old 'next_href' when switching controllers.