XML Parsing is now done from string in memory

Less IO intensive and allows for in-memory modifications of the XML.
This is done to ensure that when usesHTML is true, we automatically add
the CDATA tag to all <content>.
Should handle cases where user already added CDATA

All CDATA tags are removed *before* they're re-added in all cases. This
should ensure that all <content> tags have the CDATA tag, regardless of
whether the user added some themselves.
New audio checkbox & book info box

Added to launcher layout:
• Audio Enabled checkbox to mute audio
• Title, Author, E-mail, Website of book displayed on launcher when
selected
Changed "example" to "Info" for clarity

In the future, the 'example' will be the actual example people can read
and play.

Removed some unnecessary logging.