added support to switch layer type in map view CDB-363
added support to switch layer type in map view CDB-363

CartoDB/cartodb,codeandtheory/cartodb,bloomberg/cartodb,bloomberg/cartodb,future-analytics/cartodb,CartoDB/cartodb,bloomberg/cartodb,dbirchak/cartodb,UCL-ShippingGroup/cartodb-1,nyimbi/cartodb,raquel-ucl/cartodb,thorncp/cartodb,raquel-ucl/cartodb,bloomberg/cartodb,bloomberg/cartodb,UCL-ShippingGroup/cartodb-1,codeandtheory/cartodb,codeandtheory/cartodb,CartoDB/cartodb,dbirchak/cartodb,DigitalCoder/cartodb,splashblot/dronedb,nuxcode/cartodb,dbirchak/cartodb,splashblot/dronedb,thorncp/cartodb,raquel-ucl/cartodb,raquel-ucl/cartodb,CartoDB/cartodb,UCL-ShippingGroup/cartodb-1,future-analytics/cartodb,nuxcode/cartodb,thorncp/cartodb,future-analytics/cartodb,splashblot/dronedb,UCL-ShippingGroup/cartodb-1,future-analytics/cartodb,nyimbi/cartodb,raquel-ucl/cartodb,nuxcode/cartodb,thorncp/cartodb,DigitalCoder/cartodb,nyimbi/cartodb,codeandtheory/cartodb,nuxcode/cartodb,dbirchak/cartodb,future-analytics/cartodb,splashblot/dronedb,thorncp/cartodb,dbirchak/cartodb,UCL-ShippingGroup/cartodb-1,DigitalCoder/cartodb,DigitalCoder/cartodb,CartoDB/cartodb,nuxcode/cartodb,nyimbi/cartodb,codeandtheory/cartodb,DigitalCoder/cartodb,splashblot/dronedb,nyimbi/cartodb