[PATCH] notmuch-show: add notmuch-show-mark-read-tags option

[David Bremner]

Michal Nazarewicz <mpn at google.com> writes:

> From: Michal Nazarewicz <mina86 at mina86.com>
>
> The `notmuch-show-mark-read-tags' lists tags that are to be applied when
> message is read.  By default, the only value is "-unread" which will remove
> the unread tag.  Among other uses, this variable can be used to stop
> notmuch-show from modifying tags when message is shown (by setting the
> variable to an empty list).

Pushed,

d