Add support for property "style" to geoJson. CSS styles can be used to style geoJson features.
Merge pull request #727 from strguntbr/master

Add support for property "style" to geoJson.
change the commented out list of zoom to portal level mappings to match those in the intel site update of 2014-01-06
IITC still drops a zoom level slightly sooner at this time, but not so much now
(were niantic inspired by IITC here?)