(Bug 5265) Move greeting/footer logic into LJ::format_mail

Much easier to test, because you know the full text of the email (rather
than having to guess if you need to put a newline or not).

For the record: no need for additional newlines before/after the body.

Patch includes whitespace fixes in the text of the test emails
(Bug 5265) Make members editing work
(Bug 5265) Success messages
(Bug 5265) Cleanup

* alphabetize edit.tt.text

* remove unused variable %usernames