Clean up top-level source tree

Collect architecture independent data in 'share' subfolder.
This also matches the install path

gtk2_ardour/ardev_common.sh.in

@@ -15,15 +15,15 @@ export GTK2_RC_FILES=/nonexistent
 
 export ARDOUR_SURFACES_PATH=$libs/surfaces/osc:$libs/surfaces/faderport8:$libs/surfaces/faderport:$libs/surfaces/generic_midi:$libs/surfaces/tranzport:$libs/surfaces/powermate:$libs/surfaces/mackie:$libs/surfaces/us2400:$libs/surfaces/wiimote:$libs/surfaces/push2:$libs/surfaces/maschine2:$libs/surfaces/cc121:$libs/surfaces/launch_control_xl:$libs/surfaces/contourdesign:$libs/surfaces/websockets
 export ARDOUR_PANNER_PATH=$libs/panners
-export ARDOUR_DATA_PATH=$TOP:$TOP/build:$TOP/gtk2_ardour:$TOP/build/gtk2_ardour:.
-export ARDOUR_MIDIMAPS_PATH=$TOP/midi_maps:.
-export ARDOUR_EXPORT_FORMATS_PATH=$TOP/export:.
+export ARDOUR_DATA_PATH=$TOP/share:$TOP/build:$TOP/gtk2_ardour:$TOP/build/gtk2_ardour:.
+export ARDOUR_MIDIMAPS_PATH=$TOP/share/surfaces/midi_maps:.
+export ARDOUR_EXPORT_FORMATS_PATH=$TOP/share/export:.
 export ARDOUR_THEMES_PATH=$TOP/gtk2_ardour/themes:.
 export ARDOUR_BACKEND_PATH=$libs/backends/jack:$libs/backends/dummy:$libs/backends/alsa:$libs/backends/coreaudio:$libs/backends/portaudio:$libs/backends/pulseaudio
 export ARDOUR_TEST_PATH=$TOP/libs/ardour/test/data
 export PBD_TEST_PATH=$TOP/libs/pbd/test
 export EVORAL_TEST_PATH=$TOP/libs/evoral/test/testdata
-export MIDIPP_TEST_PATH=$TOP/patchfiles
+export MIDIPP_TEST_PATH=$TOP/share/patchfiles
 
 #
 # even though we set the above variables, ardour requires that these