Add mention of unzip dependency, fix typo
Update mapnik required version to 2.1.0

The output from carto can't be parsed by mapnik 2.0.0, even though the
symbolizers etc work fine.
Try moving road widths to variables, in order to expose the inconsistencies of casings.
Convert more widths to variables.
Disable polygon clipping for buildings. Buildings tend to be smaller than tiles
Merge pull request #51 from pnorman/building_clip

Disable polygon clipping for buildings
define variablese
temporarily alphabetize color vars, add commercial
use color variables in landcover.mss
Replace existing tile.openstreetmap.org coastline files with openstreetmapdata.com files

Closes gravitystorm/openstreetmap-carto#39

Also index the shapefiles for performance as the new ones don't come pre-indexed
Remove built up areas from shapefile from z10. It is not visible under all the residential roads.
Merge pull request #63 from pnorman/coastline_files

Replace existing tile.openstreetmap.org coastline files with openstreetmapdata.com
Change to the new world_boundaries-spherical location
update unzip commands to update files and decompress missing files
Document curl dependency

Fixes #54
Yes, this should be zoom 12
Convert _links to use variables.
Move to a standard pattern for casing widths across road types.
Use variables for tertiary widths.
Add back in colours, tweaked slightly for new casing widths.