PointTable highlights the price-setting producer
Add LOLE helper for calculting loss-of-load

* A number of required attribtues are no longer required. These were
  necessary only for determining profitability, and were not necessary
  to run the Merit order.

* Permits excluding wind or other demands from the demand curve as
  a replacement for capacity credit.
Add Curve#to_a
Revert "Add Curve#to_a"

Breaks all the things.

This reverts commit 44ff9321d5a4693a0c1c373278de248235a4e7ff.
Merge pull request #125 from quintel/lole

Add LOLE helper for calculating loss-of-load