Added support for access not granted error for ACAccountStore requestAccessToAccountsWithType

For access not granted and no account, attempt to create one or login otherwise with performLoginForNewAccount

Fixed performLoginForNewAccount to only attempt saving credentials if access was granted otherwise continue on for oauth non-native based auth

Updated non-granted response to expected dictionary type

Fixed error handler to return not successful for completionBlock on performReverseAuthForAccount

Fixed potential issue when response may not contain oauth_token or oauth_token_secret.

Fixed more potential issues with creating a NSDictionary with nil values

Fixed issue using NSJSONSerialization when data parameter could be nil.

Updated AFOAuth1Client to ~> 0.3.0

Added userInfo property kOmniAuthTwitterUserInfoKeyOverrideExistingAccount to allow overriding existing account on saveAccount if account exists already.

Refactor publicProfile string to use stringByAppendingPathComponent instead of stringWithFormat.
Merge pull request #9 from mpurland/master

Various fixes and additions