Link alias support, application name, priviledged flag, custom commands and more...

There is a lot going on here. Not sure how to proceed, but these are the features implemented:

* Support for the `command` and `privileged` parameters;
* Fix issue while using aliases on container links;
* Pulls image before running the service to force its update;
* Prefix the service name with the application name.

Let me know what you think and I might proceed differently.

Cheers.