Multiplayer: time sync of client/server (F5 display only); increase the time interval when a client can connect back (3 minutes now); apply patches suggested in bug report 1228629;
Fix bug 1181554 (RenderItem Comparer error due to Vector3.Normalize on 0 vector)
Fix bug 1120345 (Cars start oscillating, due to placing two wheelaxle on the same offset, thus all vector operations failed in computing parts location)