Fix the landcover ordering problem. Closes #15.

For detailed thinking behind the over-complicated SQL query, see the
conversation at
https://github.com/gravitystorm/openstreetmap-carto/issues/15
Remove unnecessary name column from landcover layer.
Turn off line clipping on oneway arrows.

Dasharrays and clipped lines leads to artefacts at tile boundaries.
Fix zoom levels for widest default construction lines. Closes #21
Only re-download if the server file is newer

That way you can run it again and easily get updates only. 
Also if you get to the ogr2ogr command and discover it hasn't 
been installed and you need to rerun it, get-shapefiles.sh 
won't redownload all the data again.
be explicit about the mapnik datasource plugin name to be used to read shapefiles - this avoids needing millstone to compile the stylesheet to fully complete xml
Merge pull request #32 from springmeyer/add-shape-type

Add type:shape to project.mml layer references for shapefiles
Merge pull request #31 from smsm1/patch-1

Only re-download if the server file is newer
Rearrange instance declarations as a possible workaround for #23
Move the cyclepath construction rule, otherwise the widths become too great from default rules. Refs #23.
This stuff is hairy enough to warrant a 'here be dragons' signpost. Closes #23
Add the missing line placement for construction streets. Fixes #33