Add example command

src/com/coalesce/bukkitforclojure/example/command.clj

+(ns com.coalesce.bukkitforclojure.example.command
+  (:import [org.bukkit.command CommandSender Command]
+           [org.bukkit.entity Player]
+           [org.bukkit Sound]))
+
+(defn clojureCommand
+  [^CommandSender sender
+   ^Command command
+   ^String label
+   #^"[Ljava.lang.String;" args]
+  (.sendMessage sender "You successfully ran a command in Clojure.")
+  (if (instance? Player sender)
+    (let [player (cast Player sender)]
+      (.playSound player (.getLocation player) (Sound/BLOCK_NOTE_BASEDRUM) 1.0 1.0)))
+  )
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