feat(remote-video): convert remote video menu to react

- Create new React Components for RemoteVideoMenu and its
  buttons
- Remove existing menu creation from RemoteVideo
- Refactor RemoteVideo so all function binding happens once in
  the constructor, removing the need to rebind when updating
  the RemoteVideoMenu
- Allow popover to append and remove React Components from itself
- Refactor popover so post-popover creation calls are broken out and
  popover removal behavior is all done in one function.

react/features/remote-video-menu/components/RemoteVideoMenuButton.js

@@ -0,0 +1,76 @@
+import React, { Component } from 'react';
+
+/**
+ * React {@code Component} for displaying an action in {@code RemoteVideoMenu}.
+ *
+ * @extends {Component}
+ */
+export default class RemoteVideoMenuButton extends Component {
+    /**
+     * {@code RemoteVideoMenuButton}'s property types.
+     *
+     * @static
+     */
+    static propTypes = {
+        /**
+         * Text to display within the component that describes the onClick
+         * action.
+         */
+        buttonText: React.PropTypes.string,
+
+        /**
+         * Additional CSS classes to add to the component.
+         */
+        displayClass: React.PropTypes.string,
+
+        /**
+         * The CSS classes for the icon that will display within the component.
+         */
+        iconClass: React.PropTypes.string,
+
+        /**
+         * The id attribute to be added to the component's DOM for retrieval
+         * when querying the DOM. Not used directly by the component.
+         */
+        id: React.PropTypes.string,
+
+        /**
+         * Callback to invoke when the component is clicked.
+         */
+        onClick: React.PropTypes.func
+    };
+
+    /**
+     * Implements React's {@link Component#render()}.
+     *
+     * @inheritdoc
+     * @returns {ReactElement}
+     */
+    render() {
+        const {
+            buttonText,
+            displayClass,
+            iconClass,
+            id,
+            onClick
+        } = this.props;
+
+        const linkClassName = `popupmenu__link ${displayClass || ''}`;
+
+        return (
+            <li className = 'popupmenu__item'>
+                <a
+                    className = { linkClassName }
+                    id = { id }
+                    onClick = { onClick }>
+                    <span className = 'popupmenu__icon'>
+                        <i className = { iconClass } />
+                    </span>
+                    <span className = 'popupmenu__text'>
+                        { buttonText }
+                    </span>
+                </a>
+            </li>
+        );
+    }
+}