introduce new all-in-RAM MIDI datastructure and use it for MIDI playback

libs/ardour/smf_source.cc

@@ -34,6 +34,7 @@
 #include "pbd/file_utils.h"
 #include "pbd/stl_delete.h"
 #include "pbd/strsplit.h"
+#include "pbd/timing.h"
 
 #include "pbd/gstdio_compat.h"
 #include <glibmm/miscutils.h>
@@ -213,6 +214,8 @@ SMFSource::close ()
 	/* nothing to do: file descriptor is never kept open */
 }
 
+extern PBD::Timing minsert;
+
 /** All stamps in audio samples */
 samplecnt_t
 SMFSource::read_unlocked (const Lock&                    lock,