[notmuch] Prototype of --show option to control what is shown.

Here is a set of 3 patches to implement (some) output control. [PATCH 1/3] rename option to select output format to --format from --output. [PATCH 2/3] notmuch-show.c: make calls to format functions conditional The first two are essentially suggestions for Scott. In particular the first is

[notmuch] Prototype of --show option to control what is shown.

Here is a set of 3 patches to implement (some) output control. [PATCH 1/3] rename option to select output format to --format from --output. [PATCH 2/3] notmuch-show.c: make calls to format functions conditional The first two are essentially suggestions for Scott. In particular the first is