These CONNECT subroutines need a rewrite.

(1) All pointers could be removed so that the static data can be assigned
    easily without dirty hacks.
(2) All the recursive subroutines could be removed and the final pathway
    extracted via a call to DIJKSTRA.

Replacing the extractpath routine with Dijkstra is the first thing to do,
since a number of routines could probably then be eliminated.

Keeping the structure of the subdata elements in the structure types for
MIN and TS could still be useful. Keeping track of S/F status also tells
us when we have a connected path, so this could be kept as well.
