feat(multiple block post): Swift and Disk

Deuce:
    POST v1/{vaultname}/blocks
        -Request body : msgpacked content of
                        dictionary of blockid
                        and blockdata
Swift:
    Asynchronous multiple block post
    py27 - gevent
    py33,34 - aiohttp and asyncio
            - lacks exception handling
Disk:
    Reference Driver
    Synchronous multiple block post
Hmm...probably better to create a generic None-enforcing rule here, right? If I'm reading this correctly, `val_block_id` never gets called, right? How about:

    def val_none_value(value):
        if value is not None:
            raise ValidationFailed("Value must be None")

    ReqNoneRule = Rule(val_none_value(empty_ok=True), lambda: _abort(404)) 

Thoughts?