This updates our JavaScript codebase to fix some typing issues and to

make it easier to compare HTML elements in testing.
We now set a global reference to the babel-plugin-django-gettext

types, which provides a merged Underscore.js + Gettext type for _.

This allows us to use _.funcs() as normal while also properly

localizing strings using the _ prefix.
Modules may also now use declare to declare types . This is useful for

classes that want to type a definition on the prototype that will be set

elsewhere (such as via the @spina decorator).
Unit tests that compare elements will now see the HTML of both values in

any error messages. This is done by registering a custom object

formatter that works with HTMLElement and subclasses. This just uses

the outerHTML of each value.

Unit tests pass.
Made use of all of this in in-progress changes.