Fix for getting sbgnml file map properties

[okg21]

Fix related to the newt issue https://github.com/iVis-at-Bilkent/newt/issues/689. Now the sbgnml files properties are being returned correctly.

In mainUtilities.getMapProperties in 'sbgnml' format conditional branch there exist an incorrect function call. The function is not called, but do we need to call this function in a proper way?

mainUtilities.getMapProperties = function() {
  if( elementUtilities.fileFormat !== undefined){
    if( elementUtilities.fileFormat == 'sbgnml'){
-      this.showNodesSmart
+      return sbgnmlToJson.mapPropertiesToObj();
    }
    else if(