Add note in project.clj explaining java.classpath dependency

Author: tggreene

project.clj

@@ -8,6 +8,9 @@
                  ^:source-dep [cheshire "5.8.0"]
                  ^:source-dep [org.clojure/tools.analyzer.jvm "0.7.1"]
                  ^:source-dep [org.clojure/tools.namespace "0.3.0-alpha3"]
+                 ;; Not used directly in refactor-nrepl, but needed because of tool.namespace
+                 ;; and the way MrAnderson processes dependencies
+                 ;; See https://github.com/clojure-emacs/cider/issues/2176 for details 
                  ^:source-dep [org.clojure/java.classpath "0.2.3"]
                  ^:source-dep [org.clojure/tools.reader "1.1.1"]
                  ^:source-dep [cider/orchard "0.3.0"]