Gives invalid paths when field names contain "." characters

```
[ernie@eahimac3 git]$ echo '{ "field.name": "field.value" }' | python ~/bin/show_struct.py
.field.name -- field.value
[ernie@eahimac3 git]$ echo '{ "field.name": "field.value" }' | jq .field.name
null
[ernie@eahimac3 git]$
```