Comment replies using keyboard accessory

This replaces the 3 different comment replying experiences with a single experience provided by `InlineComposeView`

(See #612)

## General Strategy

In order to handle different keyboard modes (iPad docked vs split) and different keyboard sizes the commenting UI is implemented as a `[UIResponder inputAccessoryView]` and provides a delegate `InlineComposeViewDelegate` protocol to allow other components to handle user input.

![screen shot 2013-12-16 at 12 07 23 pm](https://f.cloud.github.com/assets/19795/1758351/f88148c8-668d-11e3-8517-a5001c9111f0.png)
_composing comment on iPhone_

![screen shot 2013-12-16 at 12 08 52 pm](https://f.cloud.github.com/assets/19795/1758356/055d8200-668e-11e3-8396-fcf0c7d200d3.png)
_composing comment on iPad_

![screen shot 2013-12-16 at 12 10 24 pm](https://f.cloud.github.com/assets/19795/1758365/26fed38c-668e-11e3-880a-c5f2c78615b2.png)
_composing comment on iPad with split keyboard_


By default the `InlineComposeView` does not display any UI until it becomes the first responder and uses a hidden`UITextView` to activate the built in keyboard and assigns the `[UIResponder inputAccessoryView]` to display the toolbar above the keyboard. 

Additional benefits of using a `[UIResponder inputAccessorView]` is that the keyboard notification `userInfo` will include this view in it's frame calculations so `UITableViewController` will automatically update the `contentInset` for the controller's view. This means we no longer have to finagle the controller's views when the keyboard is displayed nor do we need to care where the keyboard is since it will always be attached to the keyboard.

__Reader__: `ReaderCommentPublisher` is a utility that replaces the networking portion of the `ReaderCommentFormView` and allows the `ReaderPostsViewController` and the `ReaderPostDetailViewController` to reuse the same delegate to reduce code duplication (fixes #754).

__Comment Notification__: The comment notification experience is pretty much the same other than using the new input method.

__Me/Blog/Comments__:`ReplyToCommentViewController` has been replaced with the `InlineComposeView`.