First version of incremental score calculator.

Currently just a dumb copy of the simple calculator.
Feasibility requirement 4 now incremental.
Workaround feasibility requirement now incremental.
Minimal release date now incremental.
Simpler way of calculating due date.
Cache also the overall due date.
Update upperBound so that it behaves more incremental.
Better code structure for the future.
Due dates now fully incremental.