Allow working with default input type and frames

- Allow set_field_value to recognize that an input element with no type defaults to the text type
- Ability to descend frame and jump back to root frame
- Before, if an input field has no type set, we could not set its value and working with frames was impossible without some hacking. Now, set_field_value recognizes that an input field with no type defaults to the text type and we can work with frames by going down the hierarchy using descend_frame or jumping right up to root using ascend_to_root_frame