TumblrManager *_tbTumblr = [[TumblrManager alloc] initWithDelegate:self];
 [_tbTumblr authenticateWithEmail:username andPassword:password];

-(void)tumblrManager:(TumblrManager *)tumblrManager didReceivedAuthenticationInfo:(BOOL)userIsLogged {
   if (userIsLogged)
      //success
   else
      // not success
 }