Min System capacity is not used in the table

[Naigege]

For transformer and diesel generator, NP3 isn't using min system capacity available in the table, if the demand node requires less than the min system capacity. For now, we can add another small capacity (like 1 kVA or 1kW), and make the raw cost very big.

[invisibleroads]

The new behavior is

1. Use values from minimum capacity row if desired capacity is less than minimum
2. Use values from maximum capacity row if desired capacity is greater than maximum
3. Interpolate values from two rows closest in value to the desired capacity

https://github.com/SEL-Columbia/infrastructure-planning/blob/master/tests/test_macros.py

[invisibleroads]

It looks like I fixed a different issue, where it was interpolating raw_cost_per_unit_capacity, maintenance_cost_per_year_as_percent_of_raw_cost, lifetime_in_years incorrectly. dcbe9a3 should fix the interpolation error.

You wanted to set a minimum on actual_system_capacity, which should be fixed by eeebc76. Please verify.