模仿c#的委托, 写的c++委托。功能与c#的类似，但是支持了更多的全局函数委托，静态函数委托，和类函数委托，比c#支持的更加的广泛。-Mimic the c# delegate, write c++ commission. Function and the c# similar, but supports the more global functions entrusted static function delegate, delegate and class functions, sup