lint: Fix many no-unused-vars eslint rule violations.

These have been carefully audited by tabbott to ensure they are
unlikely to cause regressions.

static/js/referral.js

@@ -93,7 +93,7 @@ $(function () {
         }
     });
 
-    $("#referral-form input").on('blur', function (e) {
+    $("#referral-form input").on('blur', function () {
         if ($("#referral-form input").val() === '') {
             validator.resetForm();
             resize.resize_page_components();