#11 Character set handling

[Pavel Fedin]

Character set handling in IlohaMail is completely
wrong. Here is the patch which attempts to fix this.
The basics are:
1. The browser should get all the frames in the same
encoding (that was not true in the original version if
i select character set different from $lang_charset for
my selected language).
2. "Character set" field in settings section is really
my default character set for sending mails. But viewing
mails should be done in language's character set (see
note 1). This is also the default encoding for mails
which don't have character set specification. Original
version attempts to convert all the messages to the
selected character set for viewing, this confuses
Mozilla if for example outer frame is in CP1251 and
inner frame is in KOI8-R (this patch started as adding
support for this russian encoding).
Please check this with other languages and UTF-8 (if
anyone uses it for mails).

[Pavel Fedin]