Improvements in turn restrictions

The latest version of mkgmap now has much better support for restriction relations.

Here are the main things that are newly implemented:

• Restrictions that prohibit going between two node via a particular way.
• restrictions no_entry or no_exit
• specific vehicle type, e.g. type=restriction:motorcar or restriction:motorcar=no_u_turn
• fixes possible error if different roads connect the same nodes (old code possibly saved the restriction for the wrong road)
• detects obsolete restrictions, e.g. when a oneway doesn't allow to enter the road or when the restiction applies to motor_vehicles only and the road is a cycleway.
• if the style creates multiple routable ways for one OSM way, the restriction is added for all needed combinations

There are a lot of bug fixes too, so it should all work a lot more smoothly. Use version r3189 or higher for all the fixes.