Major features and changes implemented since Workshop 2:
* Allow no fuels
* Change loading levels to percentage of capacity in heat rate curves
* Optional auxiliary consumption
* Cost input units are now per MW/MWh (not per kW/kWh)
* Implement variable O&M curve
* Add period index to heat rate and variable O&M curve inputs
* Support for specifying RPS targets as percent of load
* Support for specifying reserves as percent of load
* Linked subproblems
* Flexible units