Change fadeAnimation to true for the Leaflet map

Author: prushforth

web-map.html

@@ -231,7 +231,7 @@
             // there is a better configuration than that, but at this moment
             // I'm not sure how to approach that issue.  
             // See https://github.com/Maps4HTML/MapML-Leaflet-Client/issues/24 
-            fadeAnimation: false
+            fadeAnimation: true
           });
 
           // optionally add controls to the map