Add back enlive dependency
Fix pallet.clj project file creation

The creation of parent directories was incorrect.
Throw on unsupported clojure version

Adds a top level form to pallet.task to throw when using an unsupported version
of clojure.  This should give a less cryptic error message in that situation.
Fix message formatting in project-init task
Update for stevedore with resolved function position

Fixes #164.