Add McDonnell Douglas 500 helicopter

[TitanNano]

A second helicopter will be added.

Specs:

Name	McDonnell Douglas 500
Max Altitude	N/A
Top Speed	N/A
Rate of Climb	N/A
Mass	N/A
Capacity	N/A

Original Model Reference:
https://github.com/CahootsMalone/maxis-mesh-stuff/blob/880ae37375a7926ef4a5554fdc6735d35f2ecc88/Info/Mapping%20from%20SimCopter%20meshes%20to%20SimCity%202000%20buildings.csv#L236