use a process-queue to avoid xtables errors
Merge pull request #6 from bmeck/queuedSpawn

* Added queued spawn support to prevent XTables concurrency fail lock.
* Added an `iptables.dump` method to parse out `iptables-save`.
* Added an `iptablables.check` method to check the existence one or more rules from the selected chain.
Removed `offsprint` form `package.json`.
`iptables.utils`:

* Removed specific `comments` match in favor of the `matches` object.
* Fixed issue function don't processing correctly negated argument (with leading '!').
Added basic support for tests.
Changed code style to match overall style.
Renamed `cmdQueue` to `queue`.
Added tests and concurrency information to documentation.
README: Added Contribute section.
README: FIxed minor styling.
Removed ending space.
Removed empty lines. Changed code style to match overall style.
README: Improved docs.
Added basic tests for all `iptables` methods.
CHANGELOG: Updated with latest changes.
Version bump.
use "has" instead of home rolled hasOwnProperty wrapper