Created a new Dijkstras Algorithm to use different keys for the nodes_to_search priority queue
Different dijkstra algorithm using different key for the priority queue
Instead of setting, connected_node.update_count = 0 when we process the
neighbor, set curr_node.update_count = 0 like the original algorithm.
format
Changed the key to the domination value
Creating new branch to contain warmstarting option.  This allows boundary nodes within a region to pre-compute distances to each other, which should speed up the multi-origin dijkstra computation.
Domination value is now working with warmstart!
Boundary node labels are now stored as Numpy Arrays instead of python lists.  Significant performance increase.
Generalized PQ key to a function on the Node object, and improved testing code.
Improved documentation and naming conventions on test code.  Created get_boundary_nodes() method in the Nodes class for better organization.
adding an arcflags output file for consistency
Merge branch 'warmstart'

Branc 'warmstart' contained code which allows the multi-origin Dijkstra search to start with additional information (i.e. the pairwise distances between boundary nodes).  It also optimizes by changing the labels to Numpy arrays.  These changes seem to improve performance, so they are being added to the master branch.