[WIP] Add support of ng-pattern for text and textarea fields

This add support of ng-pattern
```json
 {
        "key": "firstName",
        "type": "text",
        "label": "First Name",
        "placeholder": "Jane",
        "pattern": "/^[a-zA-Z0-9]*$/"
    },
    {
        "key": "about",
        "type": "textarea",
        "label": "Tell me about yourself",
        "placeholder": "I like puppies",
        "pattern": "/^[a-zA-Z0-9]*$/",
        "lines": 4
    }
}
```
i will update the README, if it is ok.