libata dev guide updated

Just made a run through the libata docs, updating them for the latest hooks and filling in missing details like locking/context documentation. I've been playing with lulu.com self-publishing, and published this newly updated libata Developer's Guide there as a short book (92 pages):

	http://www.lulu.com/content/130446

I think the muddy road on the front cover is apropos :)

This guide continues to be open source -- just run "make pdfdocs" in the kernel source tree.

A PDF of the book is available for free on lulu.com or at http://www.kernel.org/pub/linux/kernel/people/jgarzik/libata.pdf or by running "make pdfdocs" (or "make psdocs", "make htmldocs", ...).

The source code for the guide is in the kernel source tree, with new additions in the 'docs' branch of rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git