Fixed problem with FeatureGroup and LayerGroup.

Author: Igor-Vladyka

README.md

@@ -221,11 +221,6 @@ List of pre-registered layers available for printing:
 If you want to override any of those, please register your own builder for them.
 
 ### Important notes
-````
-Currently if you want to use layerGroup or featureGroup to print groups of layers,
-please create a group, add all items to it and only then add a group on the map.
-````
-
 ````
 Unfortunately 'Custom' mode is not working correctly for Leaflet v.0.7.7 in all IE browsers.
 ````