Bug 905208 - Implemented the banner when a new message of a thread arrive

Bug 905208 - WIP some reviewer's request changed

Bug 905208 - WIP some reviewer's request changed

Bug 905208 - Implement the Banner link as a reusable thread_ui's object

Bug 905208 - Review suggestions implemented

WIP

WIP

WIP - Unit Tests

WIP

Bug 905208 - Unit test and scroll on send implemented

Bug 905208 - Review comments implemented

Bug 905208 - Reviews comments implemented

Bug 905208 - Minor changes