allow 1d length one read as scalar
A common though suboptimal practice is to write scalars as 1d, length 1. Now these are allowed to be read in h5fortran.
- Fixed excessive, incorrect warnings about auto-closing HDF5 files.
- h5write/h5read: removed "ierr" argument
- Find{HDF5,MPI}: only search gfortran paths if using gfortran
- CI: test in Debug and Release mode to catch more errors in development