1. Add function on service to clear all notifications for users
2. Add test for 1
3. Add link in Admin panel for accessing said function for a specific service
Merge pull request #15 from lloydmeta/feature/service_clear_notifications

Add 'Clear notifications' function to service for clearing all notifications belonging to users in a specific service.
Merge branch 'master' into feature/support_redis_failover
Tweaked redis failover setting