added flattr button to docs

docs/theme/nature/layout.html

@@ -10,5 +10,9 b''
 	border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
 	<img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1">
 	</form>
+	<div style="padding:5px">
+    <a href="http://flattr.com/thing/167489/RhodeCode" target="_blank">
+    <img src="http://api.flattr.com/button/flattr-badge-large.png" alt="Flattr this" title="Flattr this" border="0" /></a>
+    </div>	
 </div>
 {% endblock %}}