refactor!: finish parser migration

Finally! :)

This removes all code related to the old parser.

#65

lib/parser/classes/VerticalList.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const Parser = require('..');
+const Text = require('./Text');
+
+class VerticalList {
+  type = 'VerticalList';
+
+  constructor(data) {
+    this.items = Parser.parse(data.items);
+    this.collapsed_item_count = data.collapsedItemCount;
+    this.collapsed_state_button_text = new Text(data.collapsedStateButtonText);
+  }
+
+  // XXX: alias for consistency
+  get contents() {
+    return this.items;
+  }
+}
+
+module.exports = VerticalList;