A refactoring to:-
 * Separate lineargeom.py into route_geom_ops.py - higher level operations
   between routes, stops, segments etc - and more abstract/general linear
   geometry operations.
 * Allowed defining COMPARISON_EPSG centrally in route_geom_ops.py now
 * Various small cleanups/refactors to other scripts to e.g. turn a few long
   blocks of code into functions.