Refactor of my yowsup patch to log data from the axolotl decryption process

logging.patch

commit 9e15ce39c96a3537d2cc1e7593afccf441cb6379
Author: Fabian A. Scherschel <fab@heise.de>
Date:   Fri Apr 8 11:50:42 2016 +0200

    Changed data logging patch

diff --git a/yowsup/layers/axolotl/layer.py b/yowsup/layers/axolotl/layer.py
index 2e6f449..a639451 100644
--- a/yowsup/layers/axolotl/layer.py
+++ b/yowsup/layers/axolotl/layer.py
@@ -277,12 +277,21 @@ class YowAxolotlLayer(YowProtocolLayer):
         encMessageProtocolEntity = EncryptedMessageProtocolEntity.fromProtocolTreeNode(node)
 
         whisperMessage = WhisperMessage(serialized=encMessageProtocolEntity.getEncData())
+        
+        ### Get the received message, convert it to hex
+        ### Print it out as a logger message
+        whisperMessageHex = binascii.hexlify(encMessageProtocolEntity.getEncData())
+        logger.info("Received cyphertext: %s" % whisperMessageHex)
+
         sessionCipher = self.getSessionCipher(encMessageProtocolEntity.getFrom(False))
         plaintext = sessionCipher.decryptMsg(whisperMessage)
 
         if encMessageProtocolEntity.getVersion() == 2:
             plaintext = self.unpadV2Plaintext(plaintext)
 
+        ### Write the resulting plaintext out as a logger message
+        logger.info("Plaintext: %s" % plaintext)
+
         bodyNode = ProtocolTreeNode("body", data = plaintext)
         node.addChild(bodyNode)
         self.toUpper(node)