Updated TUTORIAL.md for Leiningen 2.3.4

Updated `project.clj` file output created by `lein new app`.

Updated references to clojure 1.4.0 with clojure 1.5.1 (current stable release.)

Updated banner text displayed by `lein repl`.

Updated output of unit tests.

Updated command required to run a single unit test as the name is different in the current `app` template.