Remove unused 'campus' style.
Remove unused 'campus' style.

This functionality is handled by the landuse layer instead. Fixes #5.

Sweetymeow/osm-bright,silph-io/osm-silph,jeffaudi/osm-hybrid,mapbox/osm-bright,saydulk/osm-bright,brelevenix/osm-bright-tregor,pinkflozd/osm-bright,makinacorpus/osm-makina,raumobil/osm-bright,yohanboniface/osm-bright