tickit.pen: Refactor over new tickit._tickit.
tickit.rect: Refactor over new tickit._tickit.
tickit.rectset: Refactor over new tickit._tickit. MutableSequence → (Sized, Iterable)
tickit.term: Refactor on new tickit._tickit.
tickit.stringpos: Refactor over new tickit._tickit.
Oops, this should be gone now.
tickit.__init__: Blank for now so tests can run properly.
tickit.rect: No longer segfaults. All tests pass.
README: Update to reflect recent activity.