add preset for route=hiking relations

This adds a preset for `route=hiking` relations.

An issue could be that we would have two very similar route presets: `route=foot` and `route=hiking`. According to the [wiki](http://wiki.openstreetmap.org/wiki/Hiking#Tags_of_the_relation), those two are equivalent, but route=hiking is used [more frequently](http://taginfo.openstreetmap.org/keys/route#values).