Changes from vamos:

copied body/*.cc
copied geometry/*.cc
copied track/*.cc
copied world/world.cc

removed geometry/Ac3d.cc

heavily modified body/gl_car.cc

modified body/suspension.cc and body/wheel.cc and track/Road_Segment.cc to not use Ac3d models
then modified them to use the terrain engine for height

gutted geometry/sample.cc

modified world/world.cc

modified body/cars.cc:
changed
      mp_car->exterior_model (m_data_dir + "cars/" + m_strings [0],
                              m_doubles [0], m_vectors [0], m_vectors [1]);
to
      mp_car->exterior_model ("cars/" + m_strings [0],
                              m_doubles [0], m_vectors [0], m_vectors [1]);
also removed midpoint stuff from propogate

modified wheel.cc, added position() function