get layer as a column, and sort by it
more robust layer-selection (constrain alphabet)
rip out ::railway attachment from ways
SQL for minor-roads-fill now coalesces railway into highway=railway_*
all railway=x styles converted to highway=railway_x
this prevents railway*highway style explosion, and
thus fixes the mapnik xml size growth induced by dropping ::railway
add "highway" column to trams query
railway rename not needed for #trams
fix up some other SQL queries to match the railway=x -> highway=railway_x transformation
(#highway-area-casing, #highway-area-fill, #roads, #trams)
Fix bridge rendering following respectorder tweak.
Now generates highway=railway_x in SQL, as do other layers
railway coalesce automatically includes "and not [highway]!=''"
Merge branch 'respectlayer' of https://github.com/danstowell/openstreetmap-carto into danstowell-respectlayer
Move to a full feature-coalesce
Re-fix project centre.