网络上email.class.php在PHP5下经常报错，修改了，亲测可用，环境阿里云PHP
PHP 5.3 ereg() "Function ereg() is deprecated Error"
ereg -> preg_match
PHP 5.3 ereg_replace() "Function ereg_replace() is deprecated Error"
ereg_replace -> preg_replace
"Delimiter must not be alphanumeric or backslash"
定界符不能是字母数字或反斜线,前后增加后"~",例如"~http://*[^\"]*\.html[^\"]*~
