Started moving the detail view into its own Fragment.

It compiles and the tests run, but this is nowhere near functional.
Field, not local var :)
Mostly works, but buttons aren't enabled yet.

Also, the author name isn't shown.
Working author view :)
Buttons work again now.
Buttons are now centered.
epub:// links are now opened through the details activity.
Communication between fragments should go through the activity.
Added split view for landscape.
Fixed crash
Added dividers.
Adds 'related' links.
Some bugfixes.
Merge branch 'master' into library_fragments
Disabled related links for now.