Fix and improve around segment play

- Avoid memory leaks if multiple --segment (-G) options are specified.
  Specifying multiple --segment (-G) options is also now available.
  For example: -G00:30-00:45 -G01:15-01:30
- Avoid segment time deviation when controlling speed up/down by user
  on the fly.
- Avoid double free opt_aq_fill_buff if --audio-buffer (-q) option is
  specified.
- Improve segment playing accuracy with CTLE_CUEPOINT to be handled
  correctly.
- Fix sample_count adjustment in apply_controls() if midi_time_ratio
  is changed.

Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>