Verlet with less memory usage

src/NN/CellList/CellList.hpp

src/NN/CellList/CellListFast_gen.hpp

src/NN/CellList/CellList_test.hpp

src/NN/CellList/CellNNIterator.hpp

src/NN/CellList/CellNNIteratorRuntime.hpp

src/NN/CellList/ParticleItCRS_Cells.hpp

src/NN/CellList/ProcKeys.hpp

src/NN/Mem_type/MemBalanced.hpp

src/NN/Mem_type/MemFast.hpp

src/NN/Mem_type/MemMemoryWise.hpp

src/NN/Mem_type/Mem_type_unit_tests.cpp

src/NN/VerletList/VerletListFast.hpp

src/NN/VerletList/VerletNNIterator.hpp