burnM

$burnM(minter,maxAmount)$

• Callable by anyone wishing to burn M on behalf of $minter$

• Decreases $owedM_{minter}$ by $amount$. M is subtracted from the caller of this function

• Calculates $maxPrincipalAmount$ to burn given current value of MinterGateway index

• Calls $burnM(minter,maxPrincipalAmount,maxAmount)$.