Extend policy optimization

[villyc]

Let's add a way in the policy optimization to consider energy use and environmental impact by fleet. There are two variable needed: EnergyConsumption and EnvironmentalImpact, and they need to occur in various disguises, i.e. as public variables in EcopathData and as properties in cEcopathFleetInput. They are both relative values, so the user decides what to enter, any single goes, default is 1. We should add them to the fleet input screen.

Next, add s new variable FoodValue(fleet, group) to optimize for food security.

Then, we’ll need to add these three variables to the policy optimization forms and also to the Ecosim/space output forms (not displayed by default)

I think these additions add a simple way to capture something useful.