Math: avoid Object.bounce, which has become costly.
Math: avoid Object.bounce, which has become costly.

Matthieu Nottale reports that Math.sin is ten times slower currently as
compared to Urbi SDK 2.2.  Commit 86539998340ece24c8bccbeaba05a9bbcb3e53b2
would be the cause.

	* share/urbi/math.u: Don't use bounce.

aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi