Update README.md

Author: PierreRaybaut

README.md

@@ -4,6 +4,9 @@ Simple example of ``guidata`` datasets embedded in an application window:
 
 <img src="http://pythonhosted.org/guidata/_images/editgroupbox.png">
 
+See [documentation](http://pythonhosted.org/guidata/) for more details on 
+the library and [changelog](CHANGELOG.md) for recent history of changes.
+
 Copyright © 2009-2015 CEA, Pierre Raybaut, licensed under the terms of the 
 CECILL License (see ``Licence_CeCILL_V2-en.txt``).