Fix some compilation warnings
Fix tests compilation
Enable snapshots and port connect on startup
vtl: overall export progress bar
vtl: remove obvious warning
ignore "external timecode is sync locked" for non timecode slaves.
make MIDI clock work once more: 
   * increase filter bandwith to make it sync faster
   * use transport_frame instead of audible_frame for calculating the loop error (thanks robin!)
   * reduce the deadzone to 0.1% (thanks robin)
midi_clock_slave.cc: report to ardour the delta that the loop sees (revert me if you object)
Make track header faders insensitive to vertical scroll-wheel events again.

This effectively reverts d235a27a, and restores the behaviour to that of
Ardour 2.
Merge branch 'patches' of https://github.com/jdekozak/ardour
Merge branch 'nsm' of https://github.com/royvegard/ardour