1.0.0 Release

Changes in 1.0.0
* Support for supplementary views
* Fine-tune `toContentOffset` even further with additional configuration options:
    * `placementAnchor` a relative anchor point for the placement calculation
    * `placementInset` an inset of the collection view frame for the placement calculation
    * `toSize` the expected final collection view size (allows for transitioning to a different size)
    * `toContentInset` the expected final content inset (allows for transitioning to a different inset)
* New Visible placement option: like Minimal, but ensures content visibility
* Ability to cancel the transition in place. Can be used to react smoothly to user input
  or screen rotation while the transition is in flight.
* Linear `transitionTime` property added to `TLTransitionLayout` for fine-tuning
  transition of elements, such as those that need to follow a different easing curve,
  delayed transition start, or different transition duration
* New function `TLConvertTimespace` for transitioning elements with simulated delay
  and duration relative to the overall transition progress
* New function `TLRelativePointInRect` for calculating a relative point for a given
  rect and point. Useful for the new `placementAnchor` option.
* Several bug fixes.