[Tagging] Rendering surface values

[Mateusz Konieczny]

Default map style has significant power in shaping how map is tagged.
Therefore I want to keep good tagging, documentation on Wiki and my
proposed rendering of surface tags in Default Map Style synchronized.

On
https://github.com/gravitystorm/openstreetmap-carto/issues/110#issuecomment-102763588
I posted proposal how surface values would be interpreted.

To all people using stone, rocky, rock, limerock, granite, cement,
bricks, brick, hard, interlock, pebbles and laterite values for surface
tag - please consider problems mentioned in my recent tagging mailing
list postings.