1.有限状态机，存放在Unity3dTool/FSM下面 按照http://wiki.unity3d.com/index.php/Finite_State_Machine 编写的适合于
unity3d的有限状态机，相较于维基百科的内容作了很小的改动，主要是添加了一个
状态改变的事件，通过这个事件，状态发生改变的时候就不要传递FSMSystem给状态
。 The FSM(Finite State Machine)scripts which used in unity3d is based on
http://wiki.unity3d.com/index.php/Finite_State_Machine .I have made a
little change.Mainly add a StateChange Event.Through the Event,it's easy
to change the state in FSMState.