[ultra] Require nrepl or clojure.tools.nrepl dynamically (fix conflict)

[elzibubble]

clojure.tools.nrepl is now officially deprecated and has been replaced with nrepl/nrepl. This commit updates all direct references to clojure.tools.nrepl to use a dynamic import that checks to see if clojure.tools.nrepl is on the path and otherwise to use the new nrepl.

As we rely on a significant amount of functionality in Whidbey/Puget, those will also need to have their references updated.

This commit fixes a merge conflict on project.clj.