Little utility function to get the frequency at a given time of day.
Refactored create_route_defs_csv.py script so useful aspects of segment
processing are re-usable as functions.
First cut at a script to calculate important stats for routes in a network,
like lengths, estimated # of buses needed, etc.
Updated a new API function to get route lists on segments.
Added:-
 * Calculation of shared routes on segments;
 * Calcs of # of buses needed in peak.