Yell Budgeting Tool: MTD Spend % and Projected Spend Calculated Wrong

The calculations are done using today as the day-of-month, but this throws off
the numbers because we only have spend data up to yesterday.

The calculations for these values should use a day-of-month of yesterday instead.

Suggested Formula for MTD Spend %:
(MTD Spend * Days In Month) / (TargetSpend * (Day Of Month - 1))

Note that for the first day of the month this equation will blow up, so a value
of 1 should be reported instead, we expected to have spent nothing before the
start of the month, and that is exactly how much we have spent so far..

Suggested Formula for Projected Spend:
(MTD Spend * Days In Month) / (Day Of Month - 1

Again, for the first day of the month this equation will blow up, so just use a
value of MTD Spend (hey we can be optimistic!)