+ Modified setModelToFaces method of itaRavenProject so as to point to materials in the first element of the face vector.
+ Added the posibility to plot surfaces normals in itaAc3dModel.m
+ modified ita_raven_demo_faces_room.m so as to reflect the above modifications
+ just updated documentation part of ita_time_window.m for compatibility with ita_generate_sweep.m