Removed spaces from top-level directory names.

Spaces tend to cause annoyances in a Unix-style shell environment.
This change fixes that.

51_Hurkle/java/src/HurkleGame.java

@@ -0,0 +1,7 @@
+public class HurkleGame {
+
+    public static void main(String[] args) {
+        Hurkle hurkle = new Hurkle();
+        hurkle.play();
+    }
+}