Rate limiter now added for total requests to API

Also added soem documentation
Fixed crash on lost dialog

The dialog is seemingly scrubbed on an orientation change. This wrecks
havoc with my callback niceness, and isn't easily detectable. :/ So just
drop the exception into the log rather than crashing.

Cleaner solution would be to notify the callback of a restart
Report NOT FOUND instead of ISE

Deleting a book not in the user's bookshelf is a common-enough error, and
we're just good HTTP citizens
Android version 1.1.0