UBDownloadManaget was adapted to use UBAsyncLocalFileDpownloader and QNetrowrkRequest bouth.

Refactored downloader for local files.

Items duplication adapted to new ideology of adding media items on the board.

Have a problem - should take care about saving original src path.

Still have some mesh with undo stack and with widget content.

Reworked resizing of items on board. Still have troubles with resizing at BottomRight resizer.

Now 1st added pixmap is selected.
All selected items is deselected after adding any new item.

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

Code was cleaned.
Corrections in removing strokes.

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.