#9 improved initialization added onAdd function that is called when layer is added to a map. this function adds event listeners to map and makes initial call to Solr via _getData.
#9 improved initialization
added onAdd function that is called when layer is added to a map.
this function adds event listeners to map and makes initial call to Solr via _getData.

spacemansteve/leaflet-solr-heatmap,spacemansteve/leaflet-solr-heatmap,LSHteam/leaflet-solr-heatmap,LSHteam/leaflet-solr-heatmap,LSHteam/leaflet-solr-heatmap