This mainly changes document mode behaviour in two ways:
1) When deleting 2+ items, a new document was selected in the list. Now, the current document is selected,
or if it has been deleted, a the first document in the list is set as
current document.

2) When deleting the last item in the trash, no document was selected.
Now, the current document is selected instead.

During trashing of multiple documents, a new document was selected
every time that one was moved to the trash -- even if it was about
to be trashed itself. This is no longer the case; the
selectADocumentOnMultipleTrashing() method was added to select the
first unselected document found (but this is currently not used, as
it seems OK to just select no document when we have just deleted a
whole selection)

When both a folder and items it contained were selected, and trashed,
the documents could sometimes be deleted twice and thus, permanently
deleted when one just intended to move them to the trash.

shutdown after emptying the trashbin

Import PDF: progress bar is not visible

QT:Sankore crashes after page shuffled on a document palette

SANKORE-329 last part of issue - refactoring virtual keyboard. source code still require testing and defect correction for Linux and Mac OS