Merge Guild back with Social

The Social tab is now a button to the top left of the chat interface. Given all of the new interface features for guilds, we didn't want to convolute the Social tab with a plethora of windows. Since we now have an expanded chat interface with Battle.net features and so on, we also feel the Social tab deserves a convenient little spot on the chat window.

It might take some getting used to, but maybe give it more than an hour or so before deciding change is bad? :)