Added UUIDs for each imported item.
Supported groups.

Groups reads fine for strokes.

Import ubz works bad with groups.

Implemented import UBZ strokes from CFF (means strokes who was exported from UBZ to CFF and imported back).
Compatible with groups.

Corrected imported text position.
Strokes for lines and polygons has the same color as fill color.

Fixed svg:a section. Now cff fully compatible with online validator http://validator.imsglobal.org/iwb/index.jsp?validate=package

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

Corrected adding items to group.
Corrected group creation.
Corrected adding items to scene - items shouldn't be added to itemsToRemove list because that list needs for cleaning undo stack.
Improved mechanism of removing "itemsToRemove".
Removed wrong deletion of mButtons list from UBGraphicsItemDelegate destructor because that buttons has Frame as parent.
Removed possible memory leak in UBBoardController::clearUndoStack. Some items was able not deleted.
tmpScene in cffReader not deletes now because ithas a proxy as parent.

Undo stack disabled ad scene loading because it is not needed there.

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

Frame buttons