Copy/Paste update

The past two days I worked on updating the Copy/Paste code. Before the Sketch was used, the Copy/Paste method simply copied the selected node and pasted it, but now we need to create the entire sub-tree for the selected node.

For sketch shapes, we create new nodes for the selected shape and all its children, with all points referencing the sketch containing the copied node.
For 3D shapes, we need to copy all the sketches referenced by the 3D shapes and all their nodes, updating the points' sketch references accordingly. For example, for a Cut Through All applied on an extruded circle we need to copy the two sketches used for extrude and then cut: