First attempt at a solution for problem #67

Need to test the answer against the site, but seems to work.  Uses an elimination
strategy by eliminating the single line path (the remaining edges that can only
be reached by a single path to the extreme right or left) based on the lower
remaining sum of each leg.
Triangle solution works, passed

Renamed the triangle problem file (added a file for the other variant of the
problem).  Solution now properly tracks the weight of each node (and stores a path
reference, unused for now).