added listen closely, not tested but should be fairly simple

listen-closely/description.md

@@ -0,0 +1 @@
+We intercepted a secret message, but we can't tell what it's saying. Maybe you can help? [super secret message](${listenclosely_wav})?

listen-closely/grader.py

@@ -0,0 +1,4 @@
+def grade(autogen, key):
+    if key.find("CAN_YOU_EVEN_HEAR_ME_YET") != -1:
+        return True, "Correct!"
+    return False, "Nope!"

listen-closely/problem.yml

@@ -0,0 +1,9 @@
+author: GenericNickname
+title: Listen Closely
+hint: 1, 16, 8000
+category: Crytpography
+autogen: false
+programming: false
+value: 50
+files:
+  - listenclosely.wav