[doc] Tuning Derby guide available in DITA

The Tuning Derby guide is now converted to DITA, and
you can download the source files along with the other
books already converted to DITA from the Derby Manuals
page at:

http://incubator.apache.org/derby/manuals/index.html

I have also made some cosmetic and organizational
changes to the Getting Started Guide and the Derby
Developer's Guide DITA files as I mentioned I would do
in previous posts.  Brenda Reyes helped me with some
of those changes, and I am resubmitting those zips
along with the Tuning Derby zip.

These changes and the package for the Tuning Derby
guide will show up on the manuals page as soon as Jean
can complete a new site build and commit.  Thanks
Jean!

FYI, the Tools and Utilities guide is the only manual
remaining to be converted to DITA, and I am working on
that now...