Complete first pass of the UI conversion to Backbone.

This commit continues in the pattern from the previous commit, removing
the `buoy_dom_hooks` where they are no longer needed and converting each
individual user interface element to a `Backbone.View` object. Notably:

* Alert button names have been standardized across the codebase.
* The `attachHandlers` method was replaced with Backbone constructors.
* Bug in `class-buoy-alert.php` when scheduling Timed Alerts was fixed.
* JSDoc syntax is now used thoroughly across the `alert.js` file. Yay!

This isn't perfect yet. There are a few parts where the lack of a real
`Backbone.Model` for our alerts are requiring some hacky things. But the
purpose of this commit was to begin the migration to a Backbone-based
structure as gradually as is sensible to do so. Models will come later.

Author: fabacab

buoy.js

@@ -92,7 +92,7 @@ var BUOY = (function () {
      * @return {number}
      */
     var countIncidentMenuItems = function () {
-        return jQuery(buoy_dom_hooks.menu_id).length;
+        return jQuery('#wp-admin-bar-buoy-alerts-menu').length;
     };
 
     return {

css/alerts.css

@@ -23,8 +23,8 @@
     padding-bottom: 0;
 }
 
-.dashboard_page_buoy_activate_alert #custom-message-alert-btn,
-.dashboard_page_buoy_activate_alert #schedule-future-alert-btn,
+.dashboard_page_buoy_activate_alert #contextual-alert-button,
+.dashboard_page_buoy_activate_alert #timed-alert-button,
 .dashboard_page_buoy_activate_alert #immediate-alert-button {
     background: #d43f3a;
     margin: 10px 0;
@@ -51,8 +51,8 @@
     height: 75%;
 }
 .dashboard_page_buoy_activate_alert #immediate-alert-button img,
-.dashboard_page_buoy_activate_alert #custom-message-alert-btn img,
-.dashboard_page_buoy_activate_alert #schedule-future-alert-btn img {
+.dashboard_page_buoy_activate_alert #contextual-alert-button img,
+.dashboard_page_buoy_activate_alert #timed-alert-button img {
     height: 100%;
     max-height: calc(100% - 32px);
     max-width: 100%;