- print error message when style assigns non-routable type in
combination with road_class or road_speed. 
Consider only ways with routable types and road_class/road_speed 
as roads.

- change RoadMerger.merge() to return the result



git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3227 25d90789-57f7-4ee0-8453-03a3dfeeeb22
improve WrongAngleFixer handling of connections between 
routable and non-routable lines

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3228 25d90789-57f7-4ee0-8453-03a3dfeeeb22