Fix a bunch of nagging styling issues
Fix a bunch of nagging styling issues

Render highway=road differently from highway=unclassified (closes #2742)
Dashed track lines are not visible on dark backgrounds (closes #657)
Improve path rendering to avoid new user errors (related #2327)
Railway platforms under construction (closes #1893)

digidem/iD,1ec5/iD,edpop/iD,morray/iD,AndreasHae/iD,kartta-labs/iD,mapmeld/iD,edpop/iD,ngageoint/hootenanny-ui,kepta/iD,AndreasHae/iD,openstreetmap/iD,energiekollektiv/openmod.sh-id,1ec5/iD,tbicr/iD,bagage/iD,1ec5/iD,digidem/iD,kepta/iD,bagage/iD,ngageoint/hootenanny-ui,openstreetmap/iD,mapmeld/iD,edpop/iD,mapmeld/iD,tbicr/iD,andreic-telenav/iD,kartta-labs/iD,ngageoint/hootenanny-ui,openstreetmap/iD,andreic-telenav/iD,zbycz/iD,AndreasHae/iD,morray/iD,energiekollektiv/openmod.sh-id,bagage/iD,zbycz/iD,kartta-labs/iD