Prompt the user for confirmation before removing an export format.

Requested by Radio SRB (http://srb.fm)
Prompt the user for confirmation before removing an export preset

Requested by Radio SRB (http://srb.fm)
fix caching of Audio+Midi metrics

MIDI track meters can either be MIDI-only or Audio+MIDI
previously they used the same ID for gain-meter static
image cache.
Merge branch 'patches' of https://github.com/jdekozak/ardour
Merge branch 'radiosrb' of https://github.com/adiknoth/ardour
fix ardvst and ardourvst (use variable or version number)
fix issue with wscript on OS X caused by earlier removal of AU_STATE_SUPPORT; in config summary use NO_PLUGIN_STATE not removed AU_STATE_SUPPORT
Fix crash when showing external send GUI
Fix 'Location window is blank' (#5538)

Call set_session() on the location window from ARDOUR_UI::set_session(),
and show_all() on the location window's LocationUI in set_session,
so that it displays the markers and ranges of the current session.
common spelling of infinity (lowercase as libc's printf)
Make CD track details visible whenever CD range is ticked.

Make the CD track details visible whenever the CD range box has been
ticked, rather than only when the user toggles the box on.
fix alignment of meters on midi-tracks
adjust mixer meter metric scale
fix race/endless loop on exit:

if gtk is going away while ardour updates the splash-screen:
Gtk-CRITICAL **: IA__gtk_main_quit: assertion `main_loops != NULL' failed
reset meters when changing metering-point or ports
fix metering when monitoring track input. (ran twice)
possible fix for crash on exit - err on the side of caution
fix/workaround window-proxy session-management

The window proxy defers construction of classes.
set_session() is called before the instances are available.
the proxy-manager only calls set_session() for SessionHandlePtr
but not the class-specific method..

fixes http://tracker.ardour.org/view.php?id=5566
fix save/restore [plugin] window pos&size (without save)
make window-manager session-aware