Rather than *reall* sending mail here, we instead have a new test
program, smtp-dummy which implements (a small piece of) the
server-side SMTP protocol and saves a mail message to the filename
provided. This gives us reasonable test coverage of a large chunk of
the notmuch+emacs code base (down to talking to an SMTP server with
the final mail contents).
This file was obviously describing the git test suite previously, and
would have been very hard to understand in the context of the notmuch
test suite. HOpefully it's easier to follow now.
This avoids "make test" emitting messages from three (3!) recursive
invocations of make. We change the invocations of the tests themselves
to occur directly from the shell script rather than having the shell
script invoke make again and using wildcards in the Makefile.
