FIX: Inputs are imcompletely escaped & saved (2.1 & 2.2)

[ikedasoji]

Inputs on admin pages are imcompletely escaped, then
the escaped values are saved (excpet 'info' property).
 This expedient solution have caused following problems:
o Input including `"' breaks HTML formatting.
o `<' is not allowed in admin/user option value (it is
replaced with '<' in many contexts).
o 'info' in admin page might break HTML formatting with
some sort of tags (e.g. '</textarea>').

This patch solve these problems. Always unescaped
value is saved (except '<script>' in 'info') and
escaped only when it is displayed as HTML.

[ikedasoji (ikedasoji)]

The file mailman-2.1.8-htmlescape.patch was added: for 2.1.8

[ikedasoji (ikedasoji)]

The file mailman-r7929-htmlescape.patch was added: for 2.2.0a1 (untested)