optionally use source/target id's instead of names when building edges

[rfdrake]

If you build an edge between two nodes in the map topology editor, then rename one of the nodes it causes the links built between the nodes to disappear.

Example:

   "edges": [
     {
       "capacity": "100G",
       "source": "Node1",
       "target": "Node2"
     },

If I were to change "Node1" to "Node 1" then this link goes away. It would be nice if I could use "source-id": "08a6bfc0-0f80-45af-92fc-7e06c2fa59ae" instead so the link can follow the node rename.

[jdugan1024]

Thanks for the bug report. We've been discussing this issue and will definitely be making a change along these lines, but I can't say for sure when it will happen.