Add unique canonical name per connector

[follower]

Initially can be of the form <board?>.<connector>.<pin> but since it's desired to expose this as a JS property it may need to changed/exposed as <connector>_<pin>, <Connector><Pin> or similar.

[follower]

Note that the separator character chosen may appear in a connector or pin name (so far I've seen $ and it may be that _ is used too), so ideally we want to pick a separator that isn't valid as an Eagle name or escape the character if it is used.

[follower]

This should be sufficient to create the desired canonical name (sans board name):

                        connector.userData.drill = drills[ i ];
                        if ( drills[ i ].elementParent ) {
+                               connector.name = drills[ i ].elementParent.getAttribute("name") + "." + drills[ i ].getAttribute("name");
                                connector.userData.element = drills[ i ].elementParent;
                        }

produces a name like so:

JP8.4

Will work on patching the library with this now.

[follower]

The generated names can be viewed in the console via:

brd.connectHoles.forEach(function(_) {console.log(_.name)})

(Note that every second connector has no name, as they're the bottom-side connectors.)

(I looked into demoing with a tool-tip for each hole but as there seems to be no standard Three.js tool-tip implementation I've just stuck with the console demo for now.)