SHTimer now has static member function GetTimerDiff() and DurationConvert().

* Finish base World and Timer class.

* Add Singleton class. (in progress).


Signed-off-by: Y.Moon <chglove@live.cn>
Fix exception in TimeLine::Update, now new timer will stored in queue when TimeLine is updating...

Add a simple timer use example.

Signed-off-by: Y.Moon <chglove@live.cn>