Fixed setting geoJSON on multiple maps in DOM
Updating icon init: if user specifies iconUrl, we must not use DefaultIcon, bacause shadowUrl won't be managed properly (if shadowUrl is not specified, leaflet will try to load default shadow image)
Merge pull request #411 from Natsu-/shadow_icon_issue

Updating icon init to obtain custom icon without shadow
Merge pull request #407 from voortwis/master

Fixed setting geoJSON on multiple maps in DOM
add support for ExtraMarkers
Merge pull request #418 from chrsnlsn/addExtraMarkers

add support for ExtraMarkers