For the next step, I want to be able to play an audio book.  I'm using "Princess
of Mars" from librivox.org as my first test case.  I've added it as a
sub-directory to this project, minus the mp3 files, which can be downloaded
using the getMp3Files script.  A Book should be created by parsing the index
file in PrincessOfMars.  It should be listed in the Bookshelf activity, and a
Chapters activity class should be written to show chapters in a book.