Introduced btActionInterface. This makes it easier to extend user-defined actions, such as vehicles and characters.

btRaycastVehicle and btKinematicCharacterController are derived from btActionInterface now.
Some cosmetic cleanup: changed sourceforce/sf.net url to bulletphysics.com.

Demos/SoftDemo/main.cpp

@@ -29,7 +29,7 @@ int main(int argc,char** argv)
 	softDemo->getDynamicsWorld()->setDebugDrawer(&gDebugDrawer);
 
 
-	glutmain(argc, argv,640,480,"Bullet Physics Demo. http://bullet.sf.net",softDemo);
+	glutmain(argc, argv,640,480,"Bullet Physics Demo. http://bulletphysics.com",softDemo);
 
 	delete softDemo;
 	return 0;