Interpret object attributes recursively

[cressie176]

The value attribute should be interpreted recursively but exclude np_content

{
    _task: 'set',
    name: 'message',
    value: {
        options: {
            header: {
                contentDisposition: 'attachment; filename="{{filename}}"'
            }
        },
        np_content: content
    }
}

The value attribute should be interpreted immediately (not recursively)

{
    _task: 'set',
    name: 'message',
    value: '@message'
}

The value attribute should not be interpreted at all

var broker = require('broker')
{
    _task: 'set',
    name: 'broker',
    np_value: broker
}