This adds the ability to mark ways with a user-defined
class in the profile. This class information will be included
in the response as property of the RouteStep object.
Recent improvements to OSRM have led to a lot of changes to the Lua scripting interface, and refactoring of the default profiles makes them slightly more abstract and difficult to grok for those writing profiles from scratch.
This is therefore an attempt to fully document the attributes that can be read and set from Lua profiles. I've done it from my own understanding and from reading the source, but I may well have missed things or mistaken them!
