v0.3.0

  v0.3.0 reintroduces an important feature. it is possible to fall back
  on a line of defaults instead of just one.

  as an example, you can do something like this:
    default = Fry::HStore.from_hash({'greeting' => 'hello'}, nil)
    store1  = Fry::HStore.from_hash({}, default)
    store2  = Fry::HStore.from_hash({}, store1)
    store2.greeting # => 'hello'