Added SingleSecondShell payload (#115)

* Add files via upload

* Update readme.md

payloads/library/SingleSecondShell/payload.txt

@@ -0,0 +1,18 @@
+LED G
+ATTACKMODE HID STORAGE
+
+# Set your language here
+LANGUAGE='us'
+
+LED R G
+# Check for switch position to make it easier for us.
+source bunny_helpers.sh
+
+if [ -f "/root/udisk/payloads/${SWITCH_POSITION}/ducky_script.txt" ]; then
+        QUACK ${SWITCH_POSITION}/ducky_script.txt
+        LED G
+else
+    LED R
+    echo "Unable to load ducky_script.txt" >> /root/debuglog.txt
+        exit 1
+fi