Adds surface=sett to bicycle profile, resolves #3649

References:
- http://taginfo.openstreetmap.org/keys/surface#values
- http://wiki.openstreetmap.org/wiki/Key:surface

features/bicycle/surface.feature

@@ -21,6 +21,7 @@ Feature: Bike - Surfaces
             | cycleway | grass                 | 120 s   |
             | cycleway | mud                   | 240 s   |
             | cycleway | sand                  | 240.1 s |
+            | cycleway | sett                  | 72 s    |
 
     Scenario: Bicycle - Good surfaces on small paths
         Then routability should be

profiles/bicycle.lua

@@ -88,7 +88,8 @@ surface_speeds = {
   ["earth"] = 6,
   ["grass"] = 6,
   ["mud"] = 3,
-  ["sand"] = 3
+  ["sand"] = 3,
+  ["sett"] = 10
 }
 
 -- these need to be global because they are accesed externaly