Sharing on Facebook, Twitter and Google+

[FIXED]     Font of navbar.
[FIXED]     A few compile fixes.
[IMPROVED]  Made properties nonatomic.
[ADDED]     Support for facebook, twitter and google+ sharing.

External/google-plus-ios-sdk/lib/GooglePlusSignIn.h

@@ -0,0 +1,67 @@
+//
+//  GooglePlusSignIn.h
+//  Google+ iOS SDK
+//
+//  Copyright 2012 Google Inc.
+//
+//  Usage of this SDK is subject to the Google+ Platform Terms of Service:
+//  https://developers.google.com/+/terms
+//
+
+#import <Foundation/Foundation.h>
+
+@class GTMOAuth2Authentication;
+@class GTMOAuth2ViewControllerTouch;
+
+// Protocol implemented by the client of GooglePlusSignIn to receive a refresh
+// token or an error. It is up to the client to present the OAuth 2.0 view
+// controller if single sign-on is disabled via |attemptSSO| in |authenticate|.
+@protocol GooglePlusSignInDelegate
+
+// Authorization has finished and is successful if |error| is |nil|.
+- (void)finishedWithAuth:(GTMOAuth2Authentication *)auth
+                   error:(NSError *)error;
+
+@end
+
+// |GooglePlusSignIn| signs the user in with Google+. It provides single sign-on
+// via the Google+ app, if installed, or Mobile Safari.
+// Here is sample code to use GooglePlusSignIn:
+//   1) GooglePlusSignIn *signIn =
+//         [[GooglePlusSignIn alloc] initForClientID:clientID
+//             language:@"en"
+//                scope:@"https://www.googleapis.com/auth/plus.me"
+//         keychainName:nil];
+//      [signIn setDelegate:self];
+//   2) Setup delegate methods |finishedWithAuth|, etc.
+//   3) Call |handleURL| from |application:openUrl:...| in your app delegate.
+//   4) [auth authenticate:YES];
+@interface GooglePlusSignIn : NSObject
+
+// The object to be notified when authentication is finished.
+@property (nonatomic, assign) id<GooglePlusSignInDelegate> delegate;
+
+// Initializes with your |clientID| from the Google APIs console. Set |scope| to
+// an array of your API scopes. Set |keychainName| to |nil| to use the default
+// name.
+- (id)initWithClientID:(NSString *)clientID
+              language:(NSString *)language
+                 scope:(NSArray *)scope
+          keychainName:(NSString *)keychainName;
+
+// Starts the authentication process. Set |attemptSSO| to try single sign-on.
+// Set |clearKeychain| to remove previously stored authentication in the
+// keychain.
+- (void)authenticate:(BOOL)attemptSSO clearKeychain:(BOOL)clearKeychain;
+
+// This method should be called from your |UIApplicationDelegate|'s
+// |application:openURL:sourceApplication:annotation|. Returns |YES| if
+// |GooglePlusSignIn| handled this URL.
+- (BOOL)handleURL:(NSURL *)url
+    sourceApplication:(NSString *)sourceApplication
+           annotation:(id)annotation;
+
+// Removes the OAuth 2.0 token from the keychain.
+- (void)signOut;
+
+@end