Fully three dimensional parallelization

OpenMX Ver. 3.8 supports a fully three dimensional parallelization for data distribution, while up to and including Ver. 3.6, the parallelization is made by a simple one-dimensional domain decomposition for a-axis of the unit cell for data distribution. Thus, users do not need to care about how unit cells are specified to achieve good road balancing. In OpenMX Ver. 3.8, a nearly equivalent parallel efficiency will be obtained without depending on choice of the unit cell vectors.