cli: add --include-html option to notmuch show

[John Lenz]

On Sun Aug  4 14:47 -0500 2013, Tomi Ollila <tomi.ollila at iki.fi> wrote:
> The next question is should we have new option as
> 
> --include-html
> 
> or as
> 
> --include-html=(true|false)
> 
> or even
> 
> --body=(true|false|text-and-html)
> 
> See --exclude option in http://notmuchmail.org/manpages/notmuch-search-1/
> and --body option in http://notmuchmail.org/manpages/notmuch-show-1/
> for comparison...
> 

I have no preference here, although I guess I would vote for
--include-html=(true|false) since adding it to --body makes the --body
options confusing: to make sense the body options should be
--body=(text|text-and-html|none) but of course you can't change that and
break the command line API.  Well, maybe you could add all three
--body=(text|text-and-html|none)  and still accept true/false for
compatibility.