Log total/skipped frames on output stop

This makes it easier to do two things:
  1.) Get the skipped frames count relative to each specific output
  2.) Make it so that getting the 'current' log will always contain
      information about skipped frames.  Before, you'd have to force the
      user to restart the program and get the last log, which was really
      annoying when you just wanted to see how the encoders were
      performing.