keyboard input stream to buttons

 - configs
   - mocking serial port
   - serial port override
   - min/max playback speed
on input, scrolls white on grey BG, from right edge to left; issues..

 - right to left -> left to right
 - prints 2nd behind when completely on screen -> no duplicates 
 - text stops near end -> go completely off screen
 - new input NOT queued/executed -> new input queued, executed