Simple security for TCP and UDP line receivers.

Addition of support for a simple plaintext 'key' in the line and UDP receiver services, the presence of this key acts as a simple means to prevent unauthorised or unwanted metric sources from using these services. For better security, please consider using AMQP.

I'm currently using this in a production environment. I opted not to mangle the metric path. 
Perhaps something more like:

    receiver_type = settings.LINE_RECEIVER_KEY_TYPE
    func = getattr(hashlib, receiver_type, None):
    if func is not None:
        comparekey = func(comparekey + timestamp).hexdigest()

something vaguely like that? I like making crypto libs pluggable where possible. Makes for less pain in the future when one is deemed unclean by the internet security gods.