create new assessor (lender state) contract

[xmxanuel]

The new assessor contract should track the state of the lender variables and should offer the
following method for update and getting values.

function currentNAV()

returns current NAV

function calculateSeniorTokenPrice(uint currentNAV)

returns seniorTokenPrice

function calculateJuniorTokenPrice(uint currentNAV)

returns juniorTokenPrice

function seniorAsset() returns (uint seniorDebt, uint seniorBalance)

updateSeniorAsset(uint newDebt, uint seniorBalance)

seniorRatioBounds()

• returns minSeniorRatio,
• return maxSeniorRatio

maxReserve(uint NAV)

• returns maxReserve