Note: Starting global declaration, and the somewhat ugly jQuery call are for JSLint.
Also written a class comment for the widget wrapper and cleaned up some Flake8 errors.
The implementation is loosely based on RelatedFieldWidgetWrapper from contrib.admin, but uses a bit more Python magic; tested only with TextInput and Textarea widgets and their admin counterparts, but with a bit of luck should work with other widgets too.
Overriden admin widgets of CharFields and TextFields and patched forms.CharField for nullable fields, so undefined translations don't get filled with empty strings when an admin form is saved (thus becoming defined in the case of a nullable field).