Catch up recent Docker features

I have successfully used these features with Docker 1.3.0 with the following configuration:
```
containers:
    test:
        image: debian
        run:
            add-host: ["foo:123.123.123.123"]
            cap-add: ["NET_ADMIN"]
            cap-drop: ["CHOWN"]
            device: ["/dev/random:/dev/randomhost"]
            interactive: true
            tty: true
```
* `crane create && crane start ` for the new command
* `docker inspect`& `cat /etc/hosts` to check the passing of the newly exposed flags
All those params could then go into a method that is called by both `Run` and `Create`, but maybe call it sth. like `CreateArgs` which returns the assembled args. Additionally, I'd move the `detach` param into `Run` then, so you don't need any special handling in `CreateArgs`.

Executing the command (below) would again be in `Run` and `Create`. I think this is cleaner and more in line with the other commands.