Import ubz works bad with groups.

1st we remove original widget, then we disable undo stack, create a copy of widget and make it a tool. Then undo stack enables back. That widget has tool as parent, so we not need to manage him by scene.

Show Desktop: "Erase all" button isn't work

Improvement of scene update flag setting

TODO:
 * nice icon
 * nice brush
 * fix draw with marker

Now coping creates a full copy of already created item. Copy has it's own content (like video, audio or folder) and stores original item properties (like locked, pos, size, freezed e.t.c.).

The old code has to be removed and remaining bugs fixed.

This is not functional.

PDF : Sankore overwrite Pdf layer to empty, after picture(shape) was "set as background"

Frame buttons