Some people (e.g: me) prefer to read their email with threaded
representation by default.
Without this commit, I have to run "notmuch-search" (autoloaded)
first to get "notmuch-tree" loaded.
(setq notmuch-search-oldest-first (not notmuch-search-oldest-first))
(notmuch-tree-refresh-view))
+;;;###autoload
(defun notmuch-tree (&optional query query-context target buffer-name
open-target unthreaded parent-buffer oldest-first)
"Display threads matching QUERY in tree view.