[mkgmap-dev] access=agricultural

I've noted that at least here in germany a lot of tracks are tagged with access=agricultural. As probably most of the users are not agrarians, I propose to include the following lines in the style/line file: (Or maybe more efficient, change the sourcecode to make 'agricultural' a synonym with 'no' and 'false') highway=* & access=agricultural {delete access; add access = no;} highway=* & motorcar=agricultural {delete motorcar; add motorcar = no;} highway=* & motorcycle=agricultural {delete motorcycle; add motorcycle = no;}