Have processTransaction reroute after settings changes.
Allow fixed junctions to move during major improvement.

This commit changes the meaning of junction having a fixed position for
the purposes of major hyperedge improvement.  These junctions can now be
moved and/or split where this would otherwise lead to confusing
topology, such as overlapping junctions with a zero-length connector
between them or unnecessary junctions bridging two connectors.

It also makes available a list of connectors that had their connections
altered durig major hyperedge improvement.