sortAtoms.f: basic quick sort to sort out the atoms in ascending order according to a given splitting direction.
Makefile: added sortAtoms dependencies.
redistribute.f: improved the internal documentation.
redistribute.f: setting the first communicator outside the loop.
redistribute.f: added some sorting of atoms for redistribution.
Added a halo flat to the atom type to show whether an atom is in the halo region.
redistribute.f: added some point to point comms.
Merged with the main repository.