various browser compatibility fixes for translation UI

We tried the translation UI on firefox and got a bunch of exceptions.

* Some event handlers are using the “event” variable without declaring it as an argument; that's created by magic in some browsers, but relying on that is deprecated.

* We don't have tabOverride(), is that from a jQuery plug-in or a specific version? We're using the jQuery packed with Meteor.

* Selectors like foo[attr="value"] need quotes in the value; most places that were using them had quotes, except for one.

Sorry, but this also includes stripping some trailing whitespace, which my editor does automatically on save.