Allow aliases in dictionaries

Peter,

What do you think to aliases in dictionaries:

     {:en  {:example {
        :bar {:baz ":en :example.bar/baz text"}
        :greeting  "Hello {0}, how are you?"
        :yo :example/greeting
        :baz2 :example.bar/baz}

Usage:

    (with-locale :en
      (is (= (t :example/yo "Bob") "Hello Bob, how are you?"))
      (is (= (t :example/baz2) (t :example.bar/baz))))

?

Benefits:
 - A little more flexibility when maintaining large translation files - e.g. you can leave legacy keys in place and not update all the code that uses them at that time.
 - You might use scopes to define a set of standard keys for a repeating class of things, but want to share the translation values.
 - General DRYness.

If you like this, you might also consider allowing 

    ...
    :bar2 :bar}
    ....
    (is (= (t :example.bar2/baz) (t :example.bar/baz)))

\- Phil