Tweaked the font choices a bit for consistency

I couldn't live with a sans serif font for the body text, so I've
switched to droid serif for now.  In addition, to maintain consistency
with the family, I've switched the monospaced font used for code
snippets to droid sans mono.

Droid was designed for on-screen use, so these may not be the best for
print, but given that I read a ton of PDFs online, I figured I'd stick
with this one for now.
Replaced the standard Latex chapter headings

The standand Latex chapter headings are dreadful.  I replaced with a
more modern looking style that I found online.
Modernized the headers on the page

Headers on the page use the same consistent look as the recently added
chapter headings.  In addition, slightly lightened the secondary text so
as to not compete with main body of text.