Draft Upgrade

Description
This tool upgrades selected objects in different ways.



Usage
the selected objects are modified/upgraded following this list (in order):
 * if there are more than one faces, the faces are merged (union)
 * if there is only one face, nothing is done
 * if there are closed wires, they are transformed in a face
 * otherwise, if possible, all edges are joind into a wire (closed if possible)