i18n and security bug fix

[Taguchi Takeshi <ta...@ff.iij4u.or.jp>]

Hi, all.

I found following bugs and probrems in websh-3.5.0.

a.websh can not deal non-ascii encoding.
if encoding system is non-ascii encoding, such as
euc-jp, or some iso-8859-SOMETHING, then page will
be broken.
Because,
- web_eval_tag() can not deal multi-byte strings.
- parseUrlEncodedFormData() fix stream encoding to binary.
Note; core of new web_eval_tag() is from tcl-rivet.
b.websh has local security probrem.
websh make tmp file for uploaded form data.
mode for this file is 644. so any local user can read them.
It should be 600.
c.some char *s should be CONST char *
d.targaet install-doc in Makefile is broken.

Now websh can deal any locales which supported on tcl encodings.
My Japanese ws3 page work correctly now.

Thanks.
Taguchi,T.