Beverage, Flow Meter Disable Keys, And Black Screen

Adds beverage to flow meter class, and adds the ability to set each
beverage as enabled or disabled by pressing the 1 and 2 keys.  They
will toggle on each key press. It also displays the tweet for 5
seconds while tweeting.
Non-Blocking Pause

Changes the pause on tweet so that the flow meters are still getting
data while you're reading the tweet.