Refactored function names and file structure

SpineGraph ==> SurfaceGraph
stuff only on graph (not map) in SurfaceGraph.hs
small, general functions in Util.hs

added lookup operators (!.), (!-) for graph data and application
operators ($.), ($-) for map data. Hid full internals of SurfaceGraph
data struture though edge and vertex data lookup still uses
structure-transparent interface.

Also, commented out some code which will only be used for tests.
Merge remote-tracking branch 'origin/master'

Messed up amended commit message. Yuck.