Implement promote-fn

Promotes a #() to a (fn []) and a (fn []) to a (defn ..).  With a prefix
argument it will promote a #() all the way to a (defn ..)

There's only one test because ecukes doesn't allow % in the spec files.
Merge pull request #81 from clojure-emacs/promote-fn

Implement promote-fn

Closes #79