Flags the scene as being modified based on the inputed value.
        
        :param      state   <bool>

def setModified( self, state = True ):
        """
        Flags the scene as being modified based on the inputed value.
        
        :param      state   <bool>
        """
        if ( state == self._modified ):
            return
            
        self._modified = state
        self.emitModifiedStateChanged()