Changes I needed to publish The SPDY Book

[eee-c]

This changeset includes everything that I did in order to publish The SPDY Book (http://spdybook.com & http://pragprog.com/book/csspdy/the-spdy-book). Some of the changes were required by @pragprog, others seem reasonable.

The changes include:

• Certain publishers prefer 7.5x9 inch paper size
• Use the "book" doctype output -- it produces better results in all formats
• Cover images for PDF, Epub, and MOBI (book/images/cover.jpg).
• Better fixed-width font-size for Kindle viewing
• Reference scribe.css as appropriate.
• Various HTML clean-up (space in LI tags, H1, H2 and H3 IDs).
• Re-use high quality epub as basis for MOBI.
• Generator for a zip containing the pdf, mobi and epub (updated README).
• Prepare the site in a separate sub-directory (prevent conflicts).
• Fix tests, add new ones.

I also added TODO notes for outstanding work in PDF generation (source code highlighting, recto page chapter starts).

NOTE: this commit rolls up all of my other pull requests and adds a lot of other stuff.

P.S. Huge thanks for this toolchain. I couldn't have pulled off the book without it.

[matthewmccullough]

Sorry it has been so long in the queue @eee-c. A few minor changes have been made that don't allow this to apply cleanly on HEAD anymore. Any chance I could ask you to rebase it onto master? I promise to apply it quickly after that. Scribe is getting a new wave of investment.

[eee-c]

@matthewmccullough Yah, I'll give it a try. The deadline for my next book is this coming Saturday. I'll get back to this early next week.

FWIW the switch to saxon was incompatible with many of the changes in this pull request. In between books, I tried to get it rebased, but was not successful. I blogged about it starting at http://japhr.blogspot.com/2011/12/code-blocks-in-git-scribe.html (follow the "next" links at the top to follow along). All of my git-scribe related work can be found at: http://japhr.blogspot.com/search/label/git-scribe.

Excited to hear work is underway!

[matthewmccullough]

The Pull Request has had significant enough divergence from the code that a clean merge isn't possible and could be a massive effort to manually merge. Might need to re-implement this PR.