I completely forgot a critical detail: we need to actually have a `dust.logLevel` which determines what level of logging actually shows up. Otherwise, as soon as `isDebug` is true, you get everything from `DEBUG` to `ERROR`.

We probably need something like:

```javascript
var levels = [DEBUG, INFO, WARN, ERROR];

dust.level = INFO;

dust.log = function(message, level) {
  var level = level || INFO;
  if (dust.isDebug && levels.indexOf(level) >= levels.indexOf(dust.level)) {
    // ... the rest of the code
  }
}
```