Integrate Grackle

[mbleigh]

I've decided that Grackle is close enough to my lightweight and "not too much magic" approach to API access that it should be the default way people access Twitter through TwitterAuth. I will be bringing in Grackle as a dependency and utilizing it instead of the current dispatcher. I will also, however, be wrapping it up so that everything still works the same and providing the same HTTP verb methods as currently. You'll just also be able to do something like this:

user.twitter.statuses.replies?(:since_id => 123)