Remove redundant function matrixColumnNamesToSet.
Pass around a distance-Map not a Q-Map.

Since the Q-Map is only used to find which two values in the
distance-Map to manipulate, it should only be generated at the time when
it's necessary. All other times, a distance-Map should be passed around.

Also made some variable name changes.
Draft version of createDMapWithConnectingNode.

The function is not yet working as intended, with a lot of the returned
edges having zero length. It's also fairly ugly and will have to be
cleaned up.

Also added the utility function lookupDistance.