Code to add ring signatures to Pseudonym Pairs now finished, based on laundromat.sol from Andrew "blackyblack" Lekar.

How it works, after the pseudonym event, everyone has to mix, the whole global population has to mix their proofs, and do so by joining mixers, incrementally, a new mixer created once the previous one is full. Very simple. There are two sets of mixers, one for NYM, another for registering for the next pseudonym event. Once a mixer group has formed, anyone can finish the transfer of their keys regardless of everyone else, so no risk of getting "locked in". The strays, as in the people who are at the end in case the population size is not evenly divisible by factors of 4, are sorted into a mixer of 3 people, at most three mixers with 3 people.