Fixes crash when account password is nil

For some reason, some accounts have a nil password (bad migration?).
If that's the case send and empty password so we get a credentials error
instead of crashing.

Ideally we shouldn't have to send bad credentials to force the login
dialog, but this is a quick crash fix.
Fixed Camera+ (and other) callbacks

When adding Google+ support we added
`application:openURL:sourceApplication:annotation:` to the app delegate.
It seems when this is implemented, iOS doesn't call
`application:handleOpenURL:`
Cancel wp.com operations on sign out

Avoids crashing if you sign out while reader is refreshing
Fix notes sync

After moderation, we weren't updating the note data, where the available
actions are stored.
Corrected a core data migration crash if the username is empty and also prevent a crash if the password is removed from the keychain
Merge pull request #51 from astralbodies/develop

Corrected a core data migration crash if the username is empty and also ...
Fixing incorrect user id sent to Quantcast.
Fixed text bug for pull to refresh on the reader.

If the user pulled to refresh on the Reader page they wouldn't see
the text change to say "Release to refresh…".

Closes #64
Merge remote-tracking branch 'upstream/develop' into develop