dropdown-list.el

[Chong Yidong]

We just received the copyright assignment for dropdown-list.el.  This is
a library that simulates "dropdown list" GUI elements by means of
overlay strings.

(This code was originally based on company-mode, which also has an
assignment and is on elpa.gnu.org; we got the assignment for
dropdown-list.el itself since it's used by YASnippet, which is also
going to be on elpa.gnu.org.)

It might be worth putting dropdown-list.el in Emacs core.  The code is
not up to Emacs standards, but it is a relatively small library, and so
should not be hard to clean up.  Has anyone taken a look at this before?
Opinions welcome.