various weirdnesses with unicode support

[Mikael Magnusson <mikachu@gmail.com>]

I've been using zsh in sv_SE.utf8 locale now for a few weeks, and it
is mostly working fine. Some things are a bit weird though.
* Pressing alt-t for transpose word doesn't work, and inserts lots of
NULLs in the command line, shown as ^@.
* NULLs aren't saved in the history, and when up-arrowing to a command
with a NULL in it, everything after it is cut off. (this one might not
have anything to do with unicode, i am too lazy to turn it off to try
and it's probably some sort of bug anyway :)
* Sometimes, strings with multibyte characters are only partially
saved in history too, like katakana PU. Maybe they contain a NULL, i
don't know.
* Having zsh in utf-8 locale but the terminal inputting for example
ISO-8859-1 makes zsh enter some weird state where it doesn't accept
input correctly. Going to a history entry with invalid UTF-8 also
seems to do weird things.

I can't provide any backtraces or something like that since zsh
doesn't actually crash anywhere.
I think there was something else too, but I can't seem to remember it right now.

-- 
Mikael Magnusson