#331 Generating drop down menu in code, fixed ontology coloration, and have mappings working. The central node has a bug though I know how to fix it. I will likely change from an explicit fetch of mappings to use a conditional expansion in the relation parser instead.
#331 Refactored edge registry, created node expansion registry to facilitate later use of the node expansion functionality, and to clean up the neighborhood expansions I had in place (they were bugged and I saw this would fix it).
#349 Merging issue 331 branch.