[TraDemGen][Dev] Updated the code to the new demand-related API of StdAir.
[TraDemGen][Dev] Updated the code to the new demand-related API of StdAir.

airsim/tvlsim,airsim/tvlsim,airsim/tvlsim,airsim/tvlsim,airsim/tvlsim,airsim/tvlsim,airsim/tvlsim,airsim/tvlsim,airsim/tvlsim