[#4721162] Corrections and updates to isomodel

 - osm2iso.rb updated from @muehleisen comments
 - changes to osm2iso.rb ported to ForwardTranslator.cpp
 - ErrorEstimation updated to support new understanding of how / format
   the data is returned from the ISOModel
 - Corrections to terrain_class calculation in ForwardTranslator.cpp
 - Update osm2iso.rb to also print the version generated by the
   ForwardTranslator.cpp for comparison