modification to previous commit
combined particle BC methods into one method applicable to diagonal cases
eliminated bug in communicating open boundary conditions
consolidating particle BC across directions
more direction consolidation
cleaning up VCtopology3D class and adding diagonal neighbors
implemented direct pcl comm to diagonal neighbors. crashing
fixed crash in previous commit (dirs->src_dirs in apply_BCs_locally())
cleaning up code (mostly deleting comments)
eliminated Timing class (was doing almost nothing)
eliminated error: MPI_Comm_free() called after MPI_FINALIZE was invoked.
corrected error w0 error in Collective.cpp spotted by Bo Peng
fixed recently introduced alignment error