TODO: Add some tasks, delete some tasks.

TODO: Add some tasks, delete some tasks.

A new item from IRC discussion, (speeding up "notmuch restore"), as
well as a bug I just hit myself, (content from citations is not being
indexed).

While here, notce that several items have recently been completed ('?'
now displays documentation, not function names; we have a search
binding from notmush-show-mode; and "notmuch new" responds to SIGINT
by flushing). Finally, the item regarding optimizing chunky searching
is irrelevant since we dropped chunky searching in favor of the much
better streamed searching.