add new method -showInView:releaseNotesText: .

[katsuyoshi]

• setupViewWithAppIdentifier:releaseNotesTitle:closeButtonTitle:completionBlock: reported releaseNotesText.
  I want to modify releaseNotesText and show it.

  [TWSReleaseNotesView setupViewWithAppIdentifier:@"XXXXXXXXX" releaseNotesTitle:[NSString stringWithFormat:@"What's new in version %@:", currentAppVersion] closeButtonTitle:@"Close" completionBlock:^(TWSReleaseNotesView *releaseNotesView, NSString *releaseNotesText, NSError *error){
      if (error)
      {
          // Handle errors
          NSLog(@"An error occurred: %@", [error localizedDescription]);
      }
      else
      {
          // Create and show release notes view
          NSString *modifiedReleaseNotesText = [NSString stringWithFormat:@"%@\n\nTo see any version information, please visit iTunes site", releaseNotesText];
          [releaseNotesView showInView:self.view releaseNotesText:modifiedReleaseNotesText];
      }
  }];