Saves the settings to the inputed filename.
        
        :param      filename | <str>

def save(self, filename):
        """
        Saves the settings to the inputed filename.
        
        :param      filename | <str>
        """
        dirname = os.path.dirname(filename)
        if not os.path.exists(dirname):
            os.makedirs(dirname)
        
        projex.text.xmlindent(self._xroot)
        xtree = ElementTree.ElementTree(self._xroot)
        xtree.write(filename, encoding=self.encoding(), xml_declaration=True)
        return True