Swizzle all UIViewController titles to fish emoji 🐠

fishytitles.m

IMP titleImp = imp_implementationWithBlock(^NSString *(__unsafe_unretained id foo){
    return @"🐠";
});
SEL titleSelector = NSSelectorFromString(@"title");
Method existingTitle = class_getInstanceMethod([UIViewController class],
                                                        titleSelector);
method_setImplementation(existingTitle,
                         titleImp);