The "date" keyword is ignored by the from_json parser

[schferbe]

The BIOME format has a keyword "date" in the top level. The Table has an attribute create_date which is None after loading a .biom file though. Could this field be parsed into the Table?

To reproduce:

from json import loads
from pathlib import Path
import numpy as np
from biom import load_table
from biom.table import Table
data = np.arange(40).reshape(10, 4)
sample_ids = ['S%d' % i for i in range(4)]
observ_ids = ['O%d' % i for i in range(10)]
sample_metadata = [{'environment': 'A'}, {'environment': 'B'},
                   {'environment': 'A'}, {'environment': 'B'}]
observ_metadata = [{'taxonomy': ['Bacteria', 'Firmicutes']},
                   {'taxonomy': ['Bacteria', 'Firmicutes']},
                   {'taxonomy': ['Bacteria', 'Proteobacteria']},
                   {'taxonomy': ['Bacteria', 'Proteobacteria']},
                   {'taxonomy': ['Bacteria', 'Proteobacteria']},
                   {'taxonomy': ['Bacteria', 'Bacteroidetes']},
                   {'taxonomy': ['Bacteria', 'Bacteroidetes']},
                   {'taxonomy': ['Bacteria', 'Firmicutes']},
                   {'taxonomy': ['Bacteria', 'Firmicutes']},
                   {'taxonomy': ['Bacteria', 'Firmicutes']}]
table = Table(data, observ_ids, sample_ids, observ_metadata,
              sample_metadata, table_id='Example Table')
file = Path('~/test.biom').expanduser()
table.to_json('me', file.open('w'))
loaded = load_table(file.as_posix())
print(loaded.create_date)  # is None
loaded_2 = Table.from_json(loads(table.to_json('me')))
print(loaded_2.create_date)  # is None

This is quite similar to #697. (I don't know why it was closed...)
Edit: It was closed because of commit b1fff87.

[schferbe]

I added pull request #771 resolving this issue...