Patch: src/en/README

[Max Bowsher]

Jonathon Mah wrote:
> Hi,
>
> I just clarified some things in the README file, and made some things
> more consistent. The main change is that the make commands must be run
> from the src/en/ directory, _not_ the book/ directory.
>
> I also added a command to validate using OpenSP. This command works for
> me; can others please confirm?
>
> All changes:
> * Fixed reference to directory where make commands must be run.
> * Added reference to HACKING file in "Hacking on the docs" section.
> * Added command to validate docs using OpenSP.
> * Consistently capitalizing Misc Docs.
> * Consistently adding periods after numbered list items.

Committed in part, but the misc-docs paragraph was wrong, so I removed it 
entirely, and xmllint is simpler to use than onsgmls, so recommending that 
instead.

Max.