Fixed a problem with how we communicate title changes.

This is the first set of changes towards resolving [this issue](https://github.com/wordpress-mobile/WordPress-iOS-Editor/issues/239).  We still need to wire the new delegate method into WPiOS.

Changes:
- Removes some old commented code.
- Cleans up the code a bit.
- The `editorTitleDidChange` delegate method was changed to `editorViewController:titleWillChange:`.  The reason for this change is that the text was is not really changed yet when we call the delegate method, which was causing issues when saving the new title in a data object in WPiOS.  The last keystroke was missed.