added getCocoaWindow()

we can make this rock solid if add

private:
    void * windowRawPointer_;

in the .h file


That will point to NULL

when we will call this for first time then it will point to window

and if is != NULL then just return the windowRawPointer_

else  run the for loop in our windows and grab it.

since GLUT is not even able to create new windows I will leave it as is for better clarity