inserted #include "errors.h" forgotten in commit fe2a01ab
created former_MPI_Barrier macro
moved MPI_Allreduce calls from .h to .cpp
commented out unused declarations in MPIdata.h
changed "ipic run" to call mpirun rather than mpiexec
added number of threads to utility/MPIdata.cpp output
issue#62: changed getVelocityDistribution to make one MPI_Allreduce call (untested)
issue#35: replaced MPI_Barrier with former_MPI_Barrier; MPI_Barrier is no longer no-op