Add the basic test case iptable

*A bacis class iptable_base for adding case in the future
*Subcase iptable_remove to check if container's iptable rules removed after stop.

I don't think this will work, because the result of ``__init__()`` is always ``None``.  I'm pretty sure you have to do like:

    nfdc = NoFailDockerCmd(...)
    nfdc.execute()