Ref citi_bike/utils mods; currently unstable.

Mod:
	py/citi_bike.py > py/city_bikes.py
		-rename module to reflect shift from specificity to NYC citi_bike
		program to universal bike programs.

	py/(city_bikes, utils).py
		-generalize citi_bike functions to universal bike functions; move them
		to utils module.
		-city_bikes module is reserved for city bike-program-specific functions,
		which include updating respective Mongo collections.
Fix utils database fxns; working order.

Fix:
	py/utils.py
		-fix setBikeDatabase() and update_bike_stations(), which were
		unfinished.