When the datumFields change in the Corpus, then new Datums have those fields. Fixes #181.
When the datumFields change in the Corpus, then new Datums have those fields. Fixes #181.

Also made it so that when you add a new datumField, the dropdown menu
and help text textareas for the "add" line are cleared again.


Former-commit-id: f85367ce62ec2cb8115ba9ad1d4ba6f02f8b2f62
vronvali/iLanguage,vronvali/iLanguage,vronvali/iLanguage,cesine/iLanguage,cesine/iLanguage,iLanguage/iLanguage,iLanguage/iLanguage,vronvali/iLanguage,iLanguage/iLanguage,cesine/iLanguage,vronvali/iLanguage,vronvali/iLanguage,iLanguage/iLanguage,iLanguage/iLanguage,cesine/iLanguage,cesine/iLanguage