Improve material tracking in MaterialPropertyController on the material move.

[gpospelov]

• Start application
• Go to Simulation, MaterialEditor -> select default material
• Push the button move-material-up

It will lead to Middle layer in LayerEditor losing an information about selected material. It will become undefined.

[gpospelov]

This happens because the moving of material consists of two actions: taking the material and inserting it back again.
During taking the material MaterialPropertyController removes the appropriate property from LayerItem. This leads to the loss of information on which material it was. Thus, after following insertion information is already lost and is not recovered.

To fix this issue we have to introduce dedicated ItemMove signaling, to avoid emitting a pair of signals (taken, inserted).