Cut, extrude and undo/redo fixes

Today I fixed the extrude mid plane bug which didn't allow us to change the extrusion type to Mid-plane for more complex shapes:



I've also improved undo/redo for solids affected by a cut operation:



and fixed cut and undo/redo for solids obtained from boolean operations. Here is an example where fuse, extrude and cut are applied to form a complex object: