Add recipe for creating leiningen templates

Also contains commits from https://github.com/clojure-cookbook/clojure-cookbook/pull/170 because my license assignment is in there. Can disentangle if you'd like - https://github.com/travis/clojure-cookbook/commit/a7ad0962de384c2db75cafd606433ba6ac176b71 is the only new commit. 

Still needs proofreading, editing, etc, but this is a good first pass.