Clean up highway area label

* Render names on all types of highway areas, not just highway=pedestrian
* Make minimum zoom level depend on area size
Correct order secondary vs tertiary highway

This resolves #862.
Remove polygon-gamma

polygon-gamma was left over from the XML conversion, and doesn't actually
seem to help anything

Fixes #73
Superceeds #867
Clean up and reformat water area SQL

This reformats the water SQL, and eliminates unused and hardly used
mistaken taggings for water.

Cross-reference #204
Don't return way_area for water areas

We're not using way_area, so don't return it
trac requests are migrated to github bugtracker
Filter out small areas and use polygon-gamma for large ones

This should fill in gaps between water bodies, prevent colouring bugs
and not over-represent water at low zooms
Turn down polygon-gamma even more for bigger areas

This completely eliminates white lines where large areas join.
Re-add highway=platform

Re-add highway=platform, and changes ordering of railway=platform versus paths.
This solves #871.

This assumes #866 is merged first.
Render ways with both highway and railway tag

Make sure that ways that have both a highway and a railway tag are rendered
both as highway and railway.

This resolves #874.

This assumes #866 and #884 are merged first.

Thanks to @kkofler.
Add a travis file

This only checks for JSON validity, but it's a start
Check the stylesheet is valid carto

We have to touch the shapefiles to make it not complain that they don't exist.
Move raceway fill to right layer

Raceway fill was in the casing rather than the fill layer. This
moves it to the fill layer.

This resolves #830.
Merge pull request #904 from math1985/raceway-order

Move raceway fill to right layer
Merge pull request #903 from pnorman/travis

Add config file for Travis CI
Merge branch 'highway-railway-overlap' of https://github.com/math1985/openstreetmap-carto into math1985-highway-railway-overlap
Merge branch 'math1985-highway-railway-overlap'
Merge branch 'trac' of https://github.com/mkoniecz/openstreetmap-carto into mkoniecz-trac

Conflicts:
	README.md
Merge branch 'mkoniecz-trac'
Merge pull request #878 from pnorman/polygon-gamma

Be selective when applying polygon-gamma to water areas, and remove a few old tags.