Bug 13112 - Add name of template file in html comment for each '.tt' file.

Bug 13112 - Add name of template file in html comment for each '.tt' file.

This patch adds the name of the .tt file as a HTML comment to OPAC and Staff client pages.

To test:
Apply patch
Open pages in OPAC and Staff client.
Make sure that a comment similar to the following appears in the source code:
<!-- TEMPLATE FILE: intranet-main.tt -->

Signed-off-by: Aleisha Amohia <aleishaamohia@hotmail.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>