Medication Days Covered calculation enhancements

This change enhances the medication days covered calculation for medication orders that require a unit conversion. For instance, a medication with a strength of 100 units/mL that was dispensed in mL but dosed in units.

This does not resolve cases where an explicit conversion is required - e.g. converting a dispensed medication in liters to the mL dose. This enhancement will be captured in a future enhancement.

Closes #1 (closed) (Our first bug!!!)