create MPI command for running tests using dedicated mpi_cmd_for function in toolkit.py (based on mympirun)

add patch to fix strange problem with incorrect output spec, that's being triggered when WRF is built with iqacml toolkit

reset CC to MPICC, requires during configure (otherwise hdf5.h include test fails becasue mpi.h is not found)
add -DgFortran to CPPFLAGS when building with GCC