Emacs Interface
---------------
+`notmuch-tree` (formerly `notmuch-pick`) has been added to mainline
+
+ `notmuch-tree` is a threaded message view for the emacs
+ interface. Each message is one line in the results and the thread
+ structure is shown using UTF-8 box drawing characters (similar to
+ Mutt's threaded view). It comes between search and show in terms of
+ amount of output and can be useful for viewing both single threads
+ and multiple threads.
+
+ Using `notmuch-tree`
+
+ The main key entries to notmuch tree are
+
+ 'z' enter a query to view using notmuch tree (works in hello,
+ search, show and tree mode itself)
+
+ 'Z' view the current query in tree notmuch tree (works from search
+ and show)
+
+ Once in tree mode, keybindings are mostly in line with the rest of
+ notmuch and are all viewable with '?' as usual.
+
+ Customising `notmuch-tree`
+
+ `notmuch-tree` has several customisation variables. The most
+ significant is the first notmuch-tree-show-out which determines the
+ behaviour when selecting a message (with RET) in tree view. By
+ default tree view uses a split window showing the single message in
+ the bottom pane. However, if this option is set then it views the
+ whole thread in the complete window jumping to the selected message
+ in the thread. In either case command-prefix selects the other option.
+
Tagging threads in search is now race-free
Previously, adding or removing a tag from a thread in a search