SolutionGuarantor: in the process of revamp'ing, based directly on CoreSolver
EndExtractor: Moved out of SolutionGuarantor/CoreSolver for use with SegmentGuarantor
SegmentGuarantor: store EndSegments for the upper bound of the stack
SolutionGuarantor: return dummy Blocks, use external EndExtractor
coresolvertest: updated to changes in SolutionGuarantor