add session prefs metadata

gtk2_ardour/preference-metadata

@@ -135,6 +135,62 @@
 
 [SECTION:Session]
 
+[audio-search-path]
+[auto-input]
+[auto-play]
+[auto-return]
+[count-in]
+[cue-behavior]
+[draw-opaque-midi_regions]
+[external-sync]
+[glue-new-markers-to-bars-and-beats]
+[glue-new-regions-to-bars-and-beats]
+[insert-merge-policy]
+[jack-time-master]
+[meterbridge-label-height]
+[midi-copy-is-fork]
+[midi-search-path]
+[minitimeline-span]
+[native-file-data-format]
+[native-file-header-format]
+[punch-in]
+[punch-out]
+[raid-path]
+[realtime-export]
+[record-mode]
+[session-monitoring]
+[show-busses-on-meterbridge]
+[show-fader-on-meterbridge]
+[show-group-tabs]
+[show-master-on-meterbridge]
+[show-midi-on-meterbridge]
+[show-monitor-on-meterbridge]
+[show-mute-on-meterbridge]
+[show-name-on-meterbridge]
+[show-rec-on-meterbridge]
+[show-region-fades]
+[show-solo-on-meterbridge]
+[show-summary]
+[slave-timecode-offset]
+[subframes-per-frame]
+[take-name]
+[timecode-format]
+[timecode-generator-offset]
+[timecode-offset]
+[timecode-offset-negative]
+[track-name-number]
+[track-name-take]
+[triggerbox-overrides-disk-monitoring]
+[use-monitor-fades]
+[use-region-fades]
+[use-transport-fades]
+[use-video-file-fps]
+[use-video-sync]
+[video-pullup]
+[videotimeline-pullup]
+[wave-amplitude-zoom]
+[wave-zoom-factor]
+
 [SECTION:Global]
 
 [afl-position]