Load the ini file and preprocess the section separator (':' in the section name (that is used for section extension) so that the resultant array has the correct section names and the extension information is stored in a sub-key called ';extends'. We use ';extends' as this can never be a valid key name in an INI file that has been loaded using parse_ini_file().
Signature
protected function _loadIniFile(string
$filename )