swap cell widgets on QTableWidget

[ulmly]

I need those widgets for graphically assinging the order of tasks (please see the attached figure). The code was originally written with Qt3 and will be now ported to Qt4.

In fact I have tried to used the Q3Table for supporting the Qt3's QTable, but the widgets are somehow freezed when the window size is altered. That's why I have decided to use Qt4. However, I should keep as most lines of code as possible.