Try moving road widths to variables, in order to expose the inconsistencies of casings.
Convert more widths to variables.
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.
Standard casing widths for tertiary roads.
Remove the residential-thin, refs #52
Convert turning circles to use markers - allows automatic fill/casing colours.
Start making turning circles automatically adjust to road width, and have same casing widths as roads on that zoom.
Tertiary turning circle widths.
Add remaining work from the roads refactoring.
Merge branch 'road-widths'
Merge pull request #76 from pnorman/curl_docs

Document curl dependency
Fix duplicate farmyard -> farmland in SQL query. Fixes #85
Merge pull request #67 from pnorman/world_planet_move

World planet move