BUG 13771: Update Tools Help Files for 3.18

BUG 13771: Update Tools Help Files for 3.18

This patch creates a helpf ile for the batch record delete tool
and updates the help files for notices and marc export.

To test:

* Visit tools > batch record deletion
* confirm help is right
* Visit tools > Notices & Slips
* confirm help is right
* Visit tools > export marc
* cofirm the help is right

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
(cherry picked from commit cee9f08bcb34a077c8a57d05e69629087e4b5e36)
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>