new drag-and-drop begin development
DND development - playlist DND
Playlist DND development
remake for add on double click from navi tree to playlist
Merge remote-tracking branch 'origin/test' into gtk3

Conflicts:
	src/foobnix/regui/engine/gstreamer.py
	src/foobnix/regui/treeview/common_tree.py
	src/foobnix/regui/treeview/playlist_tree.py
Fix adding playlist files in PlayListTree