vtl: update export information
vtl: remove xjadeo option dialog

xjadeo options (selective session restore) are only
useful for testing and debugging.
vtl: remove video-maintenance menu

* only really relevant for testing/debugging.
* the back-end functions are still used for 'normal' operation
  and called implicitly when opening/closing a video.
* call stop_video_server() when removing a video.
vtl: update session start/end only when adding (or dragging) the video
fix (?) behaviour when punching into automation write mode while the transport is moving, hopefully without breaking anything else
Merge branch 'master' of git.ardour.org:ardour/ardour
vtl: renice export dialog

* fix scale w/h min+max
* update labels and alignment
fix NSM initialization.

Possible segfault on startup if NSM is not used.
Merge branch 'nsm' of https://github.com/royvegard/ardour
Enable snapshots and port connect on startup