0.5.1: Fix bug with standard edit action handling where original might not

Fixed

• Bug where shouldUpdateViews was not getting reset correctly when first responder demand
  was fulfilled.
• FirstResponderStateChangeHandler.receive(on:) operator was not passing it's options
  to the scheduler.
• Fixed a bug in standard edit action handling where the original implementation would not get
  called if a standard edit action handling value was given but no override for the specific edit action
  existed.
• README and documentation fixes.