Fix the link-pois-to-ways handling

This includes:
* road speed and road class is calculated in a method that considers all modifying tags
* road speed and road class is modified in a copy of the GType object. This makes the handling much easier.

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@2915 25d90789-57f7-4ee0-8453-03a3dfeeeb22
Optimize logging statements in StyledConverter

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@2916 25d90789-57f7-4ee0-8453-03a3dfeeeb22