Make lingpy-compatible dictinary out of cldf main data.

def _cldf2wld(dataset):
    """Make lingpy-compatible dictinary out of cldf main data."""
    header = [f for f in dataset.dataset.lexeme_class.fieldnames() if f != 'ID']
    D = {0: ['lid'] + [h.lower() for h in header]}
    for idx, row in enumerate(dataset.objects['FormTable']):
        row = deepcopy(row)
        row['Segments'] = ' '.join(row['Segments'])
        D[idx + 1] = [row['ID']] + [row[h] for h in header]
    return D