Add blocks to customize service provider requests.

[larsxschneider]

With these blocks you can open requests in a UIWebView within app instead of safari.

Example:

AFOAuth1Client *oAuthClient = [[AFOAuth1Client alloc] initWithBaseURL:...];

MyLoginViewController *loginVC = [[MyLoginViewController alloc] init];
[m_rootViewController presentViewController:loginVC animated:NO completion:^(){}];

oAuthClient.onServiceProviderRequest = ^(NSURLRequest *request) {
    [loginVC.webView loadRequest:request];
};

oAuthClient.onServiceProviderRequestFinished = ^() {
    [loginVC dismissViewControllerAnimated:YES completion:nil];
};

[oAuthClient authorizeUsingOAuthWithRequestTokenPath:...];

[larsxschneider]

@mattt Any chance to get this in?

[mattt]

@larsxschneider Thanks for your pull request. It's an interesting feature that I thought would work well with a slightly different implementation. a550861 makes this addition with setServiceProviderRequestHandler:completion:. Let me know what you think.

[larsxschneider]

@mattt Looks good. Thanks for integrating this feature!

.... damn, I wanted onto the contributors list 😜