emacs: `notmuch-mua-new-forward-message' is not interactive

`notmuch-mua-new-forward-message' must be called from a buffer
containing a raw RFC2822-formatted message to forward.  Hence, it's
intended to be invoked programmatically through something else that
sets up this buffer (like `notmuch-show-forward-message'), not
interactively.

Remove its interactive specification and update the documentation
string to mention the requirements on the current buffer.
emacs: `notmuch-mua-new-reply' is also not interactive

Like `notmuch-mua-new-forward-message', this is meant to be invoked
programmatically by something that can provide a reasonable query
string.

In fact, `notmuch-mua-new-reply's interactive specification didn't
match its arguments, so it wouldn't have worked interactively.
emacs: Clean up a few documentation strings

Correct some grammatical errors, fix some violations of standard
documentation string formatting conventions, and be more precise.
emacs: Support overriding help and describing prefix action

Traditionally, function documentation strings are intended primarily
for programmers, rather than users.  They're written from the
perspective of calling the function, not interactively invoking it.
They're only ever displayed along with the function prototype (and
often refer to argument names).  And built-in help commands like
`describe-bindings' show the name of the command, not its
documentation.

The notmuch help system is like `describe-bindings', but tries to be
more user-friendly by displaying documentation strings, rather than
Elisp command names.  For most commands, this is fine, but for some
the "programmer description" is inappropriate for interactive use.
This is particularly noticeable for commands that take an optional
prefix argument.

This patch adds support for two symbol properties: notmuch-doc and
notmuch-prefix-doc, which let a command override its interactive
documentation and provide separate documentation for its prefixed
invocation.  If notmuch-prefix-doc is present, we add an extra line to
the help giving the prefixed key sequence along with the documentation
for the prefixed command.
emacs: Improve interactive use documentation

This improves the function documentation for many interactive
commands, either by improving their documentation string where the
improvement also makes sense for programmatic use or by adding a
'notmuch-doc property where it doesn't.

For nearly all commands that support a prefix argument, this adds a
'notmuch-prefix-doc property to document their prefixed behavior This
omits prefix documentation for a few commands where I thought the
prefixed behavior was too obscure (or too complex to fit in one line).
News for Emacs help improvements
database: Add notmuch_database_compact_close

This function uses Xapian's Compactor machinery to compact the notmuch
database. The compacted database is built in a temporary directory and
later moved into place while the original uncompacted database is
preserved.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
notmuch-compact: Initial commit of CLI

Introduce the user command exposing the new compaction facility.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
notmuch-compact: Add man page

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
emacs: Improved `notmuch-describe-keymap' documentation
emacs: distinguish tag `flagged' on terminal

Change foreground color to `blue' like lines representing threads
with flagged messages in notmuch-search.  Before tag `flagged' was
shown in notmuch-show buffers as image star on graphical frames while
there was no visible distinction to other flags on terminal frames.
test: set mail host in emacs_deliver

One test (reply to encrypted message in the crypto test) recently
started failing on some systems. The failure I saw were two extra
lines of the form
<87d2nbc5xg.fsf@host.i-did-not-set--mail-host-address--so-tickle-me>

The test pipes the output through

grep -v -e '^In-Reply-To:' -e '^References:'

which would normally these two ids but it does not, in this case,
because they are so long they get put on a separate line in the output.

To fix this we set mail-host-address for emacs deliver. example.com
seems a sensible address to use. This is short enough that we don't
get the line breaks above and the tests then all pass.
contrib: pick: update notmuch-show calls

Remove some unneeded nil arguments in notmuch-show calls.
Merge branch 'master' of git://notmuchmail.org/git/notmuch