Setters should emit an event so that Dapps can detect important changes to storage.
Instances include:
All the functions editing the currencies and complications of the exchange should emit an event
function addCurrency
function addComplication
function removeCurrency
function removeComplication
function updateMatchExecutor
function updateStakeLevelThreshold
function updatePenalties
function updateInfinityTreasury
Emit an event in all setters.
