Add tests for line z-indexing.
Add tests for line z-indexing.

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