[PATCH v4 0/3] emacs: do not call notmuch show for non-inlinable parts

[Dmitry Kurochkin]

Changes:

v4 since v3:

* Use $(()) instead of expr(1) for math.

v3 since v2:

* Use read function instead of cat(1) to read counter value.
* Add a newline after the count value in state file and
  notmuch_counter_value() output.

v2 since v1:

* Rename $notmuch_counter variable to $notmuch_counter_command.
* Rename notmuch_counter() function to notmuch_counter_value().
* Fix documentation for notmuch_counter_value().
* Removed unneeded and add missing "|| return" in notmuch_counter_reset().
* Coding style fixes.