refactored messages thread state name
Added feed leader as a global style for all feed activity.
Added styling for user events and dedicated events.
Refactored span on event type and added angular expression for activity likes.
Replaced with HTML5 header tag
Replaced with imgPlaceholder constant
Migrated group header to partial and added an ngInclude
Event scope is object to detect if current user is an admin or member of the event.
New activity service.
New activity service delete method and directive