JSON and cPickle Binary WED Reader/Writer

- WED can be written to either a binary file or a human readable JSON file.  The JSON is well formatted and quite large due to white space.  The reader / writer are embedded into the WED and utilize only built-in libraries.
- Added an edges pointer.  Without this we do not have an accurate count of the number of edges.  We need to know all edges to be able to tag points to edges.  Eberly, isolated 2 edge feature is a prime example of why just using enum_links_region does not work.
- Added LISA and Moran's I.  These just count (rates).  LISA assumes that we run a lot internally (black box) and the user gets counts.  Moran's I (along with the LISA notebook) illustrate how to manually get the mapping and assign the obs based on some attribute.
- Added edge_length using ps.cg.standalone point distance.  This should allow for ratio of obs count to length.  Need to talk about how we want this API to look for the end user.
- Added a brute force, outside of network checker.  This is super inefficient and added just to test the logic.  It should be refactored once the other WED issues are handled.
- Update to shp2graph to conform to the new WED API.