Debug modules in response to tests; refactor.
Debug modules in response to tests; refactor.

	- Change semantics of addresses and tags to centralize decoding
	  in ModuleManager
	- Debug MBOXModule: address handling, message generation
	- Debug MixmasterSMTPModule: handle options sensibly; enable module
	  as needed.
	- Refactor isPrintable from _escapeMessage
	- Clarify XXXX comments
        - Rename 'deliverMessages' to '_deliverMessages'
	- Rename 'DeliveryQueue.queueMessages' in 'queueDeliverMessages' to
	  avoid confusion with Queue.queueMessages, which it doesn't really
	  override.

nmathewson/mixminion,rxcomm/mixminion,Javex/mixminion,reezer/mixminion,nmathewson/mixminion,reezer/mixminion,reezer/mixminion,Javex/mixminion,mixminion/mixminion,rxcomm/mixminion,mixminion/mixminion,mixminion/mixminion,rxcomm/mixminion,Javex/mixminion,Javex/mixminion,crooks/mixminion,rxcomm/mixminion,reezer/mixminion,crooks/mixminion,nmathewson/mixminion,crooks/mixminion,crooks/mixminion,nmathewson/mixminion,mixminion/mixminion