Mike validation

Automatically execute validation function on actions if available
added ignore of webpack to validate.js
```javascript
var validate = _.isFunction(params.validation) && params.validation() || _.noop;
```

`_.noop` will return `undefined` which should work fine here, if you absolutely need to have `null` you can do `_.identity(null)`.

I imagine that you might want to validate that what `params.validation()` returns is a valid function too.