Fixed deprecation warnings

[sergeyklay]

The each function has been DEPRECATED as of PHP 7.2.0. Relying on this function is highly discouraged.

*Messages* buffer:

[DEBUG]:  AC-PHP: PHP Stack trace:
[DEBUG]:  AC-PHP: PHP   1. {main}() /.../elpa/ac-php-core-20190329.738/phpctags:0
[DEBUG]:  AC-PHP: PHP   2. include() /.../elpa/ac-php-core-20190329.738/phpctags:10
[DEBUG]:  AC-PHP: PHP   3. deal_config() phar:///.../elpa/ac-php-core-20190329.738/phpctags/bootstrap.php:253
[DEBUG]:  AC-PHP: PHP   4. deal_file_tags() phar:///.../elpa/ac-php-core-20190329.738/phpctags/deal_config.php:335
[DEBUG]:  AC-PHP: PHP   5. PHPCtags->process_single_file() phar:///.../elpa/ac-php-core-20190329.738/phpctags/deal_config.php:237
[DEBUG]:  AC-PHP: PHP   6. PHPCtags->struct() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:875
[DEBUG]:  AC-PHP: PHP   7. PHPCtags->struct() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:247
[DEBUG]:  AC-PHP: PHP   8. PHPCtags->struct() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:516
[DEBUG]:  AC-PHP: PHP   9. PHPCtags->struct() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:247
[DEBUG]:  AC-PHP: PHP  10. PHPCtags->struct() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:394
[DEBUG]:  AC-PHP: PHP  11. PHPCtags->struct() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:247
[DEBUG]:  AC-PHP: PHP  12. PHPCtags->get_scope() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:571
[DEBUG]:  AC-PHP: PHP  13. each() phar:///.../elpa/ac-php-core-20190329.738/phpctags/PHPCtags.class.php:900

@xcwen Could you please rebuild phpctags