All of SXEmacs' http URLs are now https. WooHoo!

All of SXEmacs' http URLs are now https.  WooHoo!

I used this shell snippet  to create this changeset...

for sub in www git issues downloads; do
    git grep -l http://$sub.sxemacs|grep -v ChangeLog.d|
       xargs sed -i "s@\(http\)\(://$sub.sxemacs.org\)@\1s\2@"
done

Signed-off-by: Steve Youngs <steve@sxemacs.org>