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)
remove compilation warning
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