[Koha] Sending orders by email

[Edgar Fuß]

I should add a few clarifications to that preliminary proof-of-concept-patch:

-- The patch is against the installed koha tree (since that's what I patched during development), not (as it, of course, should become in the long run) against the source tree.
-- The (german-language) Template included in the enhancement request is meant solely as an example on how to use the <item> and <total> patterns. It's not even what you would really send to a german-speaking book seller.
-- To try the patch, you need to create a new letter/notice/mail template along the lines of said example under the new module name ``orders'' with code ``ORDERMAIL''. Of course, that's just the names I chose during development and subject to change.

Any feedback, suggestions etc. welcome.