Give U1DB file a .db extension

There's now a apparmor rule to give permission for the database files in
the default location, but *only* if it has an extension of .db.  See
Launchpad bug #1224126.  Closes #19.
Improved font management

Ship Bitstream Charter, URW Bookman L, and URW Gothic L, since they
don't come on the phone.  Also, decide between the Droid, Nimbus, and
Free families based on what's available for an additional serif and
sans-serif font.
New icon
Decrease technical level of dialogs

Notably, don't refer to "~/Books"
Revert "Avoid binding loop for height"

This reverts commit c9dc8ee428a095e73e643a8ebd10146c98f309ec. It was
causing the wrong toolbar to be shown when Beru was first opened.