v0.2

• Make Embed an instance of Ord
• Provide NFData instances for all the combinators.
  Depend on 'deepseq'
• Re-implement freshen' and gfreshen using a free monad to give
  GHC a chance to inline it all away. This changes the type of
  gfreshen. Major version bump.
  • Expose FFM, liftFFM and retractFFM
• Start benchmarking some of the operations (particularly unbind).