Merge remote-tracking branch 'geo_steve/master'

Merge in changes from GeoSteve/leaflet-providers to add more ESRI.
Merge remote-tracking branch 'tmcw/mapbox-layers'

Get mapbox updates from tmcw/leaflet-providers /mapbox-layers
Merge branch 'dev/add_openweathermap'
Merge branch 'dev/add_options_param'