Background colour for contextmenu
Fix highlight bug
Labels draw before un-rotating
Tidy up events
Deal with pixel ratio after resize
History recorded and each tree kept : need to put most recent at the top and remove subsequest trees
Release v1.0.6
Thumbnail order reversed, closes #17
Release v1.0.6-1
Remove previous trees, close #16
Release v1.0.6-2
Release v1.1.0-0