add code to handle hooks for simulation steps.
add code to handle hooks for simulation steps.

git-svn-id: e886c6aed492beb28f167ab2f23d4509dc3d3d26@662 00316523-1ed1-4fdc-9313-76483a3f41dc

jorik041/insight,killbug2004/insight,killbug2004/insight,jorik041/insight