Add rising bollard exception to barriers for car profile.

This handles `barrier=bollard` with `bollard=rising`, by making an
exception to the barrier whitelist. Barriers tagged as such do no longer
require an explicit access tag.

This also adds corresponding tests, check this out:

    cucumber --tags @barrier

References:

- http://wiki.openstreetmap.org/wiki/Tag:barrier%3Dbollard
- http://wiki.openstreetmap.org/wiki/Key:bollard
- https://github.com/Project-OSRM/osrm-backend/issues/1616

profiles/car.lua

@@ -195,7 +195,11 @@ function node_function (node, result)
   else
     local barrier = node:get_value_by_key("barrier")
     if barrier and "" ~= barrier then
-      if not barrier_whitelist[barrier] then
+      --  make an exception for rising bollard barriers
+      local bollard = node:get_value_by_key("bollard")
+      local rising_bollard = bollard and "rising" == bollard
+
+      if not barrier_whitelist[barrier] and not rising_bollard then
         result.barrier = true
       end
     end