- fix communication with cameras when a scripted sequence has to be
  run again or multiple times (the current version allows to repeat
  a scripted sequence only if cameras are switched off and on)
- more robust scripting, add more functions
- mirror lockup?
- allow delta-time scripts
- allow setting scripting sequence at a paricular time in scripts
  (pressing enter is not suitable in all cases)
- windows port
- investigate the 400D communication protocol