expose Decimal in wf conditions

wcs/qommon/publisher.py

@@ -131,7 +131,9 @@ class QommonPublisher(Publisher):
 
     def get_global_eval_dict(self):
         import datetime
-        return {'datetime': datetime}
+        from decimal import Decimal
+        return {'datetime': datetime,
+                'Decimal': Decimal}
 
     def format_publish_error(self, exc):
         get_response().filter = {}