add ::baue_near, for local growth: a variant of ::baue
* simcity.cc: use new growth code
* dings/gebaeude.cc: tweak growth code for testing
* simworld.cc: tweak passenger level for testing
* freight_list_sorter.cc: avoid "Unknown destination" for commuters on
  their way to a depot.
* vehicle/simvehikel.cc: tweak growth code