add RPATH linking for HDF5

update my_machine.arch for Intel compilers

increment version in input variables list

prepare release 3.1

last update to RELEASE.md

release notes for version 2.F

fix undefined MPI_COMM_WORLD when MPI is not used

FCFLAGS is more standard than FFLAGS

RELEASE.md typos

bug fix in the OpenMP directive in hartree potential with RI