Allow move tool to move multiple pieces

[Timo van der Laan]

For puzzles like 630 it would be a great help if we could somehow move multiple pieces as if they where one.
One possibility would be to be able to say to the cutpoints that they are frozen for the move tool.

[drumpeter18yrs9yrs]

I would find this very useful since I use a lot of cutpoints in a puzzle. i always have to close the cutpoints, move, then reopen the cutpoints.