Onscreen authentication: Add fast path for current/recent users

[mik3y]

Make it easy for active users (those in the current session) to authenticate quickly, ie without a lot of scrolling and hunting for their avatar.

Maybe we could eschew the "recent events" list on the home screen (which is somewhat boring?) for a list of (avatar, name, session total), & trigger authentication against that user on auth.

[theguardian]

Agree that users currently in a session should float to the top (with maybe a yellow container outline) of the drinkers list.

I also think we should make the session stats and recent activity views in the UI optional. Maybe add another option for fast-path for authentication of session drinkers. The right side of the screen feels a bit crowded to me.

[geoffculp]

The recent drinkers tab that used to exist when selecting the beer me button worked really well for my drinkers (basically two clicks to select your account). I understand the drinker confusion that lead to the removal (3900cea) but it may have been easier to resolve by having the beer me button take you to the "all users" tab instead of the "recent users" tab. I'd vote for the return of the recent tab, but I also like your ideas on improving the home screen layout too.