Change pretty url parameter to @pretty to stop collision with field name.

Author: rouilj

roundup/rest.py

@@ -1536,7 +1536,7 @@ def dispatch(self, method, uri, input):
 
         # check for pretty print
         try:
-            pretty_output = not input['pretty'].value.lower() == "false"
+            pretty_output = not input['@pretty'].value.lower() == "false"
         except KeyError:
             pretty_output = True