+ * Revision 1.5 2004/04/03 03:32:05 mdw
+ * General robustification.
+ *
+ * Revision 1.4 2004/03/22 02:19:10 mdw
+ * Rationalise the sliding-window threshold. Drop guarantee that right
+ * arguments to EC @add@ are canonical, and fix up projective implementations
+ * to cope.
+ *
+ * Revision 1.3 2004/03/21 22:52:06 mdw
+ * Merge and close elliptic curve branch.
+ *
+ * Revision 1.2.4.1 2004/03/20 00:13:31 mdw
+ * Projective coordinates for prime curves
+ *