Turn "Rename Discussion" dialog into a modal, closes #616 (#1083)

* Changed "Rename Discussion" prompt into a modal.
* Added DiscussionRenameModal component (Modal)
* Changed DiscussionControls.renameAction to use the modal (I may have removed the ability to return a promise)

* Added punycode.js back to js/forum dist

* Fixed some formatting, removed some unnecessary variables

js/forum/src/components/DiscussionRenameModal.js

@@ -0,0 +1,67 @@
+import Modal from 'flarum/components/Modal';
+import Button from 'flarum/components/Button';
+
+/**
+ * The 'DiscussionRenameModal' displays a modal dialog with an input to rename a discussion
+ */
+export default class DiscussionRenameModal extends Modal {
+  init() {
+    super.init();
+
+    this.discussion = this.props.discussion;
+    this.currentTitle = this.props.currentTitle;
+    this.newTitle = m.prop(this.currentTitle);
+  }
+
+  className() {
+    return 'DiscussionRenameModal Modal--small';
+  }
+
+  title() {
+    return app.translator.trans('core.forum.discussion_controls.rename_modal.title');
+  }
+
+  content() {
+    return (
+      <div className="Modal-body">
+        <div className="Form">
+          <div className="Form-group">
+            <input className="FormControl title" placeholder={this.currentTitle} bidi={this.newTitle} />
+          </div>
+          <div className="Form-group">
+            {Button.component({
+              className: 'Button Button--primary',
+              type: 'submit',
+              loading: this.loading,
+              children: app.translator.trans('core.forum.discussion_controls.rename_modal.submit_button')
+            })}
+          </div>
+        </div>
+      </div>
+    )
+  }
+
+  onsubmit(e) {
+    e.preventDefault();
+
+    this.loading = true;
+
+    const title = this.newTitle;
+    const currentTitle = this.currentTitle;
+
+    // If the title is different to what it was before, then save it. After the
+    // save has completed, update the post stream as there will be a new post
+    // indicating that the discussion was renamed.
+    if (title && title !== currentTitle) {
+      return this.discussion.save({title}).then(() => {
+        if (app.viewingDiscussion(this.discussion)) {
+          app.current.stream.update();
+        }
+        m.redraw();
+        this.hide();
+      });
+    } else {
+      this.hide();
+    }
+  }
+}