Multiple fixes for performLoginWithListOfAccounts, verify_credentials api call to https, and error handling

Fixed performLoginWithListOfAccounts to call performLoginForNewAccount when granted = false and there was an error.  Fixed api call to api.twitter.com/1.1/account/verify_credentials.json to https (was getting 403 forbidden), it is https as per docs.  Fixed error when responseUser is nil but there is a raw http error in the response data but still want to throw a correct error.  Fixed saveTwitterAccountWithToken to only return an account if accounts.count == 1 otherwise throws error of domain kOmniAuthTwitterErrorDomainConflictingAccounts.