Added new options to create_gtfs_from_basicinfo.py script:
 -- delete_partials : cleans up partial GTFS files after full one created.
 -- route_write_batch_size : can configure the route write batch size.

 If route write batch size is larger than the number of routes to process, it
 just saves to GTFS directly, and doesn't write any partial files along the
 way that have to be re-loaded.

 (Useful if you have a system with plenty of RAM for generating the GTFS).
Added some new funcs to save route avg headways all stops to gtfs_ops.py
Two new useful scripts to create, and then modify, a set of average
frequencies, for all routes.
Changed member attribute functions setup_for_route() and setup_for_trip_set()
to return a Bool stating if the setup was successful. Useful in case these
functions are potentially called for service periods not handled by a route.
Added ability to use get_network_stats.py function to calculate # of vehicles
needed for a network with varying segment speeds per route, per time period.
Fixed GTFS stop ID tuple sorting in func read_avg_speeds_on_segments()

Added new reading from file func, read_route_hways_all_routes_all_stops()

Added conversion func to reformat headway values to form used in
mode_topology_info.py:- get_tp_hways_tuples()
Tuned the way the setup flags are returned.
In func calc_seg_refs_for_route()
handled the case of only one direction of route :- in this case, add a
"reversed" to the name of the normal directions.
Added to get_network_stats() function the ability to get network vehicles
needed based on varying per-route headways.
Moved a constant to outer scope.
Minor improvement of an exception statement.
Added to increase_route_freqs.py the ability to add frequency defs for missing
service periods (So e.g. if a line only runs on weekends, this adds a weekday
service).
added a simple func to read in a timedelta.
Added proper ability to allow per_route headways in different time periods to
create_gtfs_from_basicinfo.py script.