Minor Fixes and Additions

Originally when I forked this project, the goal was to create a better response handler.  I failed at that.  The XML one does work well and I believe there might be some room for improvment like having a commong response object that has the raw results and the xml parsed object.  Another time prehaps. I did want to post a couple fixes and additions.

1) Not everyone uses Composer, so adjust the autoload script to only load if the file exists
2) Config Override for all options and not just the limited
3) Centralize config name list
4) Add constats for UrlMapper
5) Fix static methods and change static calls to object calls
6) Get description methods for Address Response and Card Response