Addition of several unpaved road types to avoid_unpaved profile as well ...

...as some barrier types
Unpaved road types added are quite common in OSM data, as a filtering of planet shows. Below figures are only for residential highways:
      60998     gravel
      31056     ground
      24754     dirt
      21959     paving_stones
      10772     sand
       9281     compacted
       1273     pebblestone
       1100     grass
        346     mud
        227     earth
        224     fine_gravel
        182     wood