Recompute convex hull if xy_offset changes
Recompute convex hull if xy_offset changes

With room for more settings.

Contributes to issue CURA-2407.

hmflash/Cura,Curahelper/Cura,ynotstartups/Wanhao,Curahelper/Cura,ynotstartups/Wanhao,fieldOfView/Cura,hmflash/Cura,fieldOfView/Cura