Find values with '#parents' structure.

... Or at least a similarly-built structure... The old method of "tracking" would lead to false-positives when fields were similarly named at different levels in the hierarchy, so something as follows would have the potential to break down:
```
authors
- 0
-- given
-- family
host
- authors
-- 0
--- given
--- family
```
didn't seem to cause errors in output of eventual submissions ('cause we're only changing the things we're AJAXing)...

PHP errors start popping up if the structure varies slightly... Say that host authors use a `tags`/`tag` structure to allow multiple values for both given and family names instead of a plain `textfield`.