GNU ELPA structure

[Stefan Monnier]

Currently, GNU ELPA contains sufficiently few packages, that a flat list
is OK, but will soon become inconvenient for end-users.

So we should start thinking about how to structure the space of
ELPA packages.  I think a first division is between packages that only
provide functions for use by other packages (which I'd call "libraries")
and "end-user packages" which provide commands the user can use directly.

After that we could either have a tree structure (somewhat like the
subdirs in `emacs/lisp'), or otherwise rely on "tags", which would
probably be taken from the "keywords:" package header.


        Stefan