fixes ZEN-9726

Initial implementation for persistent connection to send encrypted message to windows.  Subclassed twisted Agent, HTTP11ClientProtocol, and Request according to the changes found in twisted ticket 3420:  http://twistedmatrix.com/trac/ticket/3420.  Applied the changeset and the additional diffs.  Changed single global Agent to one Agent per RequestSender to send requests in a single persistent connection.  Attach gssclient to RequestSender for encryption/decryption.  Encrypt message before sending and unfortunately decrypt in multiple areas due to multiple Protocols for receiving data.  
odd.  not sure why that showed up, but it is used on line 83