Restore the state of the credolib workspace from a pickle file.

def restoredata(filename=None):
    """Restore the state of the credolib workspace from a pickle file."""
    if filename is None:
        filename = 'credolib_state.pickle'
    ns = get_ipython().user_ns
    with open(filename, 'rb') as f:
        d = pickle.load(f)
    for k in d.keys():
        ns[k] = d[k]