Bug#213465: HTTPS support (Progeny)

[Jeff Licquia <licquia@progeny.com>]

Package: apt
Version: 0.5.9
Severity: wishlist
Tags: patch

(Patch sent separately; a previous version of this message, with the
patch, was bounced by the bug mail server.)

Here is the Progeny version of the patch to add SSL support to apt. 
This patch is derived from the work of Tomas Pospisek
<tpo@sourcepole.ch>.

Our main innovation is to merge the http and https methods into one
binary, with https as a symlink to http.  This was done so that
redirects could be made from http to https and vice versa.  (See our
other patches for the redirect/auth patch.)

One important consideration: there may be some confusion on our part
regarding the license.  Tomas seemed to have received permission to link
OpenSSL with apt, but the only documentation of this is in Tomas's patch
itself, and there's some question as to whether the license grant was
legit.  If there is a problem, we will implement GNU TLS right away, as
we are distributing binaries of this patch now.

Another concern that I've heard: binding SSL support so tightly to apt,
and thus adding another dependency to the base system.  I'm open to
ideas regarding this problem if it's considered important.

This patch is against vanilla apt 0.5.9.  We can also produce patches
against our redirect/auth and cookie version of 0.5.9, or can migrate to
newer apt versions, as needed.