support hashes in resource attributes

there is a chance that resource will be something along those lines...
````
    my::defined::check { "it's about time":
        command         => {
            "ntp"   => "check_ntp -H 127.0.0.1",
            "clock" => "/usr/local/bin/check_clock.sh -w 5 -c 10", 
        },
    }
````
let's make it supported!

now it just yells:
````
Error: can't convert Hash into String
````