changes in ext/mbstring (PHP_4_3)

ext/mbstring/mbfilter* and some related files were developed as the general library to convert multi-byte character encoding and these files were bundled with PHP since PHP 4.0.6. The original library is developed as libmbfl in sourceforge.jp. (You can obtain libmbfl from http://cvs.sourceforge.jp/cgi-bin/viewcvs.cgi/php-i18n/libmbfl) The bundled files (mbfilter*) with PHP are replaced the bundled version of libmbfl in CVS head branch (PHP5-dev). These changes are to minimize the difference of the original library and the bundled version with PHP and to minimize the developing effort. I have plan to commit the same changes to PHP_4_3 branch. If someone has problem with these changes, please let me know. Rui -- Rui Hirokawa <rui_hirokawa@ybb.ne.jp>