Bug 19743: Update header and footer on each item for checkin / checkout / renewal...

Bug 19743: Update header and footer on each item for checkin / checkout / renewal notices

When generating the checkout notice for a patron we only update the
section in between the '---' tags

For template toolkit purposes it means we cannot affect the content
based on more than a single item. For instance, we want to add the total
cost of all items checked out.

Test Plan:
1) Add "Thank you for visiting <<branches.branchname>>." to the bottom of the checkout notice. Below the second '----'.
2) Check out an item to a patron to generate that notice
3) Note the branch name in the notice
4) Update the branch name in the branches editor, change it to something else
5) Check out a 2nd item to that patron
6) Notice the items list updated, but the branch name did not
7) Apply this patch
8) Check out a 3rd item to that patron
9) Notice the branch name updated this time

Signed-off-by: Te Rauhina Jackson <terauhina.jackson@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>