Enable use of multiple Geomap plugin on page

In version 3.1.2 users will have to provide a container to hold map/legend/data. This will let users have more then one Geomap plugin by page. Web site made with older version will continue to work but they will not be able to put more then 1 Geomap plugin. If they want to do so, they will have to adapt their site to the new configuration.