dialog 1.2-20121230; closes #19045.

There have been three releases since our last update, so the changes
here span three changelogs:

* http://invisible-island.net/dialog/CHANGES.html#t20120703
* http://invisible-island.net/dialog/CHANGES.html#t20120706
* http://invisible-island.net/dialog/CHANGES.html#t20121230

p.s. I verified the GPG signature provided for the archive against
the public key on offer at the author's site:

  $ curl -OO ftp://invisible-island.net/dialog/dialog-1.2-20121230.tgz{,.asc} \
    http://invisible-island.net/public/dickey-invisible-island.txt |
    gpg --import && gpg --verify dialog-1.2-20121230.tgz.asc