Reorganised the Unicode layer somewhat: moved luni_send and

Reorganised the Unicode layer somewhat: moved luni_send and
lpage_send out into the line discipline, making them _clients_ of
the Unicode layer rather than part of it. This means they can access
ldisc->term, which in turn means I've been able to remove the
temporary global variable `term'. We're slowly getting there.

git-svn-id: svn://svn.tartarus.org/sgt/putty@2143 cda61777-01e9-0310-a592-d414129be87e