Error Details

I need to show a error rather complex error summary list, which enables the user to select a process step, focus the input field and so on.

Therefore I extended the validatable observable with a errorDetails object:
```javascript
     //make a details object summary
     observable.errorDetails = {
        rule: rule,
        params: ctx.params,
        observable: observable,
        message: observable.error
    };
```
Supplementary, I have extended the grouping parameters. 
```javascript
        grouping: {
            deep: false,            //by default grouping is shallow
            observable: true,       //and using observables
            errorDetails: false     //insert plain error messages
        }
```
If errorDetails is set to true than the errorDetail objects instead of error messages will be returned.