All test scripts to be executed are now named as T\d\d\d-name.sh,
numers in increments of 10.
This eases adding new tests and developers to see which are test scripts
that are executed by test suite and in which order.
Presently, the code which finds the parent of a message as it is being
added to the database assumes that the first Message-ID-like substring
of the In-Reply-To header is the parent Message ID. Some mail clients,
however, put stuff other than the Message-ID of the parent in the
In-Reply-To header, such as the email address of the sender of the
parent. This can fool notmuch.
The updated algorithm prefers the last Message ID in the References
header. The References header lists messages oldest-first, so the last
Message ID is the parent (RFC2822, p. 24). The References header is
also less likely to be in a non-standard
syntax (http://cr.yp.to/immhf/thread.html,
http://www.jwz.org/doc/threading.html). In case the References header
is not to be found, fall back to the old behavior.
V2 of this patch, incorporating feedback from Jani and (indirectly)
Austin.
