BitcoinKit update
backup config fixes

- run backup after enabling it
- enable notifications during wizard

fixes #217
don't enable time machine by default

if time machine is not configured, you'd be immediately greeted with a
scary "backup failed" message, before you have a chance to say anything;
on the other hand, not enabling it doesn't really change much, because
it's just a monitor, it doesn't actually control what Time Machine does