Changes to settings.sh

We added the following lines

# compilerInstall=OpenFOAM
compilerInstall=System
case "${compilerInstall:-OpenFOAM}" in
System)
    if [ -e /proc/cray\_xt ]; then
      export WM_COMPILER_DIR=$GCC_PATH
      export WM_COMPILER_BIN=$WM_COMPILER_DIR/bin
      export WM_COMPILER_LIB=$WM_COMPILER_DIR/snos/lib64
    fi
    ;;

and

MPT)
    export MPICH_PATH=$MPICHBASEDIR
    export MPI_ARCH_PATH=$MPICH_DIR
    export MPICH_ROOT=$MPI_ARCH_PATH

    _foamAddLib $MPI_ARCH_PATH/lib
    _foamAddLib $MPICH_PATH/pmi/lib
    _foamAddLib $MPICH_PATH/util/lib

    export FOAM_MPI_LIBBIN=$FOAM_LIBBIN/mpt
    ;;