Add translations credits.

README.md

@@ -49,5 +49,9 @@ Credits
 The integrated icons are part of the [Farm Fresh Web Icons](http://www.fatcow.com/free-icons) and are licensed under the
 [CC BY 3.0 US](http://creativecommons.org/licenses/by/3.0/us/)
 
-The about icon is part of the [Web Blog Icons by SEM Labs](http://semlabs.co.uk/) and is licensed under the 	
+The about icon is part of the [Web Blog Icons by SEM Labs](http://semlabs.co.uk/) and is licensed under the 
 [CC BY 4.0](http://creativecommons.org/licenses/by/4.0/).
+
+English translations when possible where copied from the used libraries. Mainly the 
+[leaflet documentation](leafletjs.com/reference.html) is used.
+