Add OpenSeaMap overlay, some style cleanup/clarification in README
Add OpenSeaMap to overlay layers.
Add Toner TerrainBackground layer
filter out mapbox
Merge branch 'master' into provider-stamen-terrain-bg
merge readme
Merge pull request #54 from leaflet-extras/rm-streets

filter out mapbox
Merge pull request #55 from leaflet-extras/master

ok I'll just merge it myself