Add ZeroVolumeSearch functionality

src/DistributeMat.c

src/DistributeMat.h

src/Heap.c

src/Heap.h

src/Makefile

src/Options.c

src/Options.h

src/SparseMatrix.c

src/SparseMatrix.h

src/SubsetSum.c

src/SubsetSum.h

src/ZeroVolumeSearch.c

src/ZeroVolumeSearch.h

tests/Makefile

tests/Mondriaan.defaults

tests/runtest

tests/testHelper_DisconnectedMatrix.c

tests/testHelper_DisconnectedMatrix.h

tests/test_DetectConnectedComponents.c

tests/test_Heap.c