list_render: Fix filtering/sorting.

This code has always been kind of convoluted
and buggy, starting with the first
sorting-related commit, which put filtering
before sorting for some reason:

    3706e2c6ba

This should fix bugs like the fact that
changing filter text would not respect
reversed sorts.

Now the scheme is simple:

    - external UI actions set `meta` values like
      filter_value, reverse_mode, and
      sorting_function, as needed, through
      simple setters

    - use `hard_redraw` to do a redraw and
      trigger external actions

    - all filtering/sorting/reverse logic on
      the *data* happens in a single, simple
      function called `filter_and_sort`

frontend_tests/node_tests/list_render.js

@@ -236,7 +236,13 @@ function sort_button(opts) {
         closest: lookup('.progressive-table-wrapper', {
             data: lookup('list-render', opts.list_name),
         }),
-        hasClass: lookup('active', opts.active),
+        hasClass: (sel) => {
+            if (sel === 'active') {
+                return opts.active;
+            }
+            assert.equal(sel, 'descend');
+            return false;
+        },
         siblings: lookup('.active', {
             removeClass: (sel) => {
                 assert.equal(sel, 'active');