Better wire separation

[tomcl]

Currently the Issie wire separation does not always make same-net wires that can overlap each other from their source port do this.

this makes it burdensome to route long connections with many bends where multiple wires follow the same route

Suggested Solution

It is not easy for wire separation to know when this behaviour is wanted. However - wire autoroute could check for an autorouted wire having the same source as a wire on the circuit and where possible follow an existing wire from its source. Routing could be implemented to all existing same-net wire vertices, or to the nearest existing segment on every existing wire, etc, and routes compared. it is not entirely clear how best to do this.