Enhancement proposal: Let 0 mean 0; use -1 as "ignore"

[cfe316]

At the moment there are certain fields, namely Max_Cap_MW, where the relevant constraint is activated only if the field's value is > 0. This is not a big problem for current resources --- if you really want a Max_Cap_MW of zero just don't have that row --- but as we introduce compound resources in the future, it will be more useful to be able to prevent certain of their subcomponents from being built, by setting their Max_Cap_X to 0.

It seems cruel to new users to have similar fields with slightly different behavior, so I think we should move toward uniformly using -1 as the "ignore" value rather than 0.

As a first cut, this should be the behavior for Max_Cap_MW, Max_Cap_MWh, and Max_Charge_Cap_MW. These changes should be very simple, just changing > to >= or similar.

For greater uniformity we might also update Max_Duration. This would require slightly changing the code which is currently just

[y in STOR_ALL], EP[:eTotalCapEnergy][y] <= dfGen[y,:Max_Duration] * EP[:eTotalCap][y]

.

[JesseJenkins]

Agreed with this suggestion. Please implement when you have time @cfe316 & @sambuddhac. 

[sambuddhac]

Agreed with this suggestion. Please implement when you have time @cfe316 & @sambuddhac. 

On to it.

[sambuddhac]

This is addressed on v0.4.0, right @lbonaldo ?