Use shelve for metadata instead of pure text

[Martin Sandve Alnæs]

To make the file more structured and extensible during replay.

[Martin Sandve Alnæs]

Maybe all metadata can be in one file "casedir/metadata.shelve"?

with shelve.open(os.path.join(casedir, "metadata.shelve")) as db:
    # Get problem params:
    pp = db["params"]["problem"]
    mu = pp["mu"]
    rho = pp["rho"]
    dt = pp["dt"]

    # Get fields and their metadata:
    for fieldname, fieldmetadata in db["fields"].items():
        ...

[Martin Sandve Alnæs]

But note that it's still nice to have params.txt, its easy to grep in.

[Øyvind Evju]

55b5ea8