moved contribution note to CONTRIBUTORS;

--- a/NEWS	Wed Nov 08 09:08:54 2006 +0100
+++ b/NEWS	Wed Nov 08 11:22:40 2006 +0100
@@ -490,8 +490,6 @@
 termination 
 by lexicographic_order
 
-Contributed by Lukas Bulwahn.
-
 * Records: generalised field-update to take a function on the field 
 rather than the new value: r(|A := x|) is translated to A_update (K x) r
 The K-combinator that is internally used is called K_record.