Add failure handling for AwaitListening

Previously, if AwaitListening failed (because the container exited
before we successfully connected), then it would return and the "Ready"
barrier would fall.

Now we look for that condition and make the "Failure" barrier fall
instead.
Add container commandline arguments
Merge pull request #24 from scraperwiki/add-args

Add container commandline arguments
Merge pull request #26 from scraperwiki/bugfix-listening

Add failure handling for AwaitListening
Don't include iptables executable
Add -p option to publish ports