Overrode TogetherJS default css to make the extension look more like Review Board.

Launch 'Chat' by clicking the Chat tab located on the right side of the header bar. The following views on any page illustrate the new changes:
-The right TogetherJS menu should be dark and similar to the header bar.

-The pop-up titled "Invite a friend" should mimic containers in the admin panel.

-Clicking on the first icon in the TogetherJS menu, the secondary menu that pops up mimics the pull down shown the Support tab in the header bar is hovered over.

-Clicking the last icon (Chat) or third icon (Audio Chat) in the TogetherJS menu, the pop-up should also mimic the containers found in the admin panel.