Adding missing files

CHANGELOG.md

example/Vector/0_simple/main.cpp

example/Vector/4_multiphase_celllist_verlet/Makefile

example/Vector/4_multiphase_celllist_verlet/main.cpp

src/Grid/staggered_dist_grid_util.hpp

src/Makefile.am

src/Vector/vector_dist_MP_unit_tests.hpp

src/Vector/vector_dist_multiphase_functions.hpp

src/Vector/vector_dist_unit_test.hpp