Increase text-dy for default shop style
explain workflow in contribution guidelines
Drop landuse=grave_yard

We still render landuse=cemetery and amenity=grave_yard.

See issue #204.
Merge pull request #768 from polarbearing/workflow-contributions

explain workflow in contribution guidelines
Merge pull request #767 from vholten/shop_names

Increase text-dy for default shop style
Merge pull request #793 from math1985/graveyard

Drop landuse=grave_yard