#55 squirrelmail use utf-8 character by Simp zh_CN

[yang zhaojun]

My modified version is 1.4.10a. The main points of the following has made some modifications:
1. If the attachment is named Chinese characters, I am able to show correct when it is downloading;
2. Email's message and attachment, if they edited by different coding (mainly the UTF-8, GB2312, BIG5, GBK encoding, etc.), in the view (for reading e-mail and viewing attachment) If it can not be displayed correctly, I add a choice of character encoding Controls allow users to choose to enable display correctly at the UTF-8 by IE.
Of course, changed code is my interest .all opinions and suggestions are welcome.thanks!

[yang zhaojun]

added some code in squirrelmail files