Fix some more ctypes issues (#2009)
Fix some more ctypes issues (#2009)

 * Make {C,WIN,PY}FUNCTYPE's restype argument optional (for void returns)
 * Make WinError return WindowsError
 * Don't have Array explicitly inherit from Sized
   (since inheriting from classes with different metaclasses causes problems, 
    and it is a protocol anyways)
 * Have Array.__iter__ properly return an Iterator instead of an Iterable
euresti/typeshed,li-dan/typeshed