Serialize state machines in the torrc

Figure out how to serialize state machines in the torrc and consensus to make it easire to specify state machines for researchers (and for common users).

Perhaps it's fine to do this after 0.4.0 since the WTF-PAD code in 0.4.0 is mainly for research purposes and not inteded to be used by a wide audience. The researchers can perhaps write code of their own that instantiates the padding machines if we write a good enough doc to do so.