Made template parser remember last initted page_id and namespace to avoid double init; made additional_headers reassign only do so if $template->additional_headers is empty (it's being blanked somehow, need to come up with a backtrace sometime)

# Used for testing mod_rewrite.
<IfModule mod_rewrite.c>
RewriteEngine on

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.*) install.php?do=modrewrite_test&str=$1
</IfModule>