SSL (patch 1)

First of many patches on SSL code.  The first patch just sets
the groundwork for future patches by pulling all SSL-specific
(and by implication all secure session) code into two new files,
be-secure.c and fe-secure.c

These files also contain a temporary checklist of pending patches:

 * PATCH LEVEL
 *      milestone 1: fix basic coding errors
 *      [*] existing SSL code pulled out of existing files.
 *      [ ] SSL_get_error() after SSL_read() and SSL_write(),
 *          SSL_shutdown(), default to TLSv1.
 *
 *      milestone 2: provide endpoint authentication (server)
 *      [ ] client verifies server cert
 *      [ ] client verifies server hostname
 *
 *      milestone 3: improve confidentially, support perfect forward secrecy
 *      [ ] use 'random' file, read from '/dev/urandom?'
 *      [ ] emphermal DH keys, default values
 *
 *      milestone 4: provide endpoint authentication (client)
 *      [ ] server verifies client certificates
 *
 *      milestone 5: provide informational callbacks
 *      [ ] provide informational callbacks
 *
 *      other changes
 *      [ ] tcp-wrappers
 *      [ ] more informative psql

Finally, because of the large number of patches (instead of a
monoblock patch) I'm managing them with CVS.  Sorry about the
$Id$ and $Header$ in the diff....

Bear