nvme-cli documentation updates

[Keith Busch]

On Wed, Oct 12, 2016 at 10:45:50AM +0200, Christoph Hellwig wrote:
> [third try, I'm really got as using the wrong list address today.  Sorry Jay.. :)]
> 
> This series improves the nvme-discover manpage a bit, and adds a new
> one for nvme-connect-all.  I would have preferred to share a page for
> both commands as there is a lot of duplication, but I couldn't find a way
> to do that.

I applied them all and regenerated the man and html pages. I had to make
one minor change to connect-all.txt to get asciidoc to understand the
header portion.

I had to fixup the multipart conent type in patches 2/3 and 3/3, and
missed J's comments while doing that. I'll apply updates on top of the
current master if we need to change any wording.