Refactor from 1 function for calcStateTax to use unique functions for each state

[m12t]

This will allow for more flexibility in capturing the idiosyncrasies of each state's tax code.

For example, 6 states allow a deduction of federal tax from taxable income. However, Oregon has a cap of $7050 on this while Iowa allows 50% of federal to be deducted up to a $10,000 cap.