NixIO is not supporting datetime attributes #6
Description
import datetime
from neo.io.nixio import NixIO as NIO
from neo import Block
b = Block(name='block1',rec_datetime=datetime.datetime.now())
nio = NIO('testfile.nix')
nio.write_block(b)
results in
File "/home/julia/repositories/python/nixpy/nixio/value.py", line 71, in __init__
raise TypeError("Invalid value type: {}".format(type(value)))
TypeError: Invalid value type: <type 'datetime.datetime'>