Fix the SSIs and remove some obsolescent .htaccess files.
The '<--#if expr...' magic I was using had stopped working. This
changeset fixes that. It also cleans up the .htaccess files (most of
which were rm'd)
* templates/header.template: Update to use "ap_expr" syntax.
* .htaccess: Use Apache 2.4.x access control with 'Require'
* changes/.htaccess: Removed. It wasn't doing anything that
wasn't aleady covered in the top-level .htaccess.
* docs/.htaccess: Ditto.
* people/.htaccess: Ditto.
Signed-off-by: Steve Youngs <steve@sxemacs.org>