Accept names in colour tag

[Hufkratzer]

In colour tag (http://wiki.openstreetmap.org/wiki/Key:colour) accept names like blue, green, pink, orange, see https://taginfo.openstreetmap.org/keys/colour#values, otherwise some routes are missing.

Example: http://mtbmap.cz/#zoom=14&lat=50.791&lon=5.431 (= http://hiking.waymarkedtrails.org/#routelist?map=14!50.791!5.431)