use 'buffer' to make echo smooth

sadly it's only smooth when starting recordaudio while device is idle
back to direct echo part 1: change back to mplayer tv://

instead of mencoder|mplayer; now with both audio and video
back to direct echo part 2: use bash array variables for INPUTOPTIONS
don't need buffer anymore
usage text
cleanup
move t2hms to Utils
stop 'stop' monkey patching, add terminate method to Process

With it, the last remnant of async and future is gone.
revert part of 'merged audio+video, part 2' (glade file)
add inputoptions to preferences dialog
check tape name for leading '/'
empty status line if ready to start

hacky: status updates are partially through update_start_button and
partially through maybe_valid_tapename_entry_text (and partially
through the toplevel). (Where are our pure functions.)
comment about possible memory leak