V2Sim 1.4.2 (with GUI)

Major difference between 1.4.1 & 1.4.2

1. Pbuy-Is-Service-Fee is added to CS generator, also fro Psell-Is-Service-Fee
2. Fix a bug in CS owners
3. Add a property for bind (node/edge element name)
4. Allow extra properties in RoadNet Edge/Node
5. New format node_type.txt is supported.
6. Add __delitem__ for VDict
7. find_best_station now calculates time in a different way. The charging power (_pc_lim1) is utilized to estimate waiting time instead of a fixed 30min. The charging time is now taken into consideration according to _pc_lim1 and _pcf.

Full Changelog: v1.4.1...v1.4.2