ffplay: remove delays when paused from video and subtitle thread

Once the frame queue is full, we will wait anyway.

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: remove manual bug option handling code

It is supported as a codec option, and those are already parsed.

Signed-off-by: Marton Balint <cus@passwd.hu>
ffplay: update documentation

Reviewed-by: Lou Logan <lou@lrcd.com>
Signed-off-by: Marton Balint <cus@passwd.hu>