Confirmation dialog: Make keyboard-accessible: escape to cancel

And proper tab order. Then some more work to re-focus on the message
composition field after the dialog shows up and steals focus.

FREEBIE

js/views/conversation_view.js

@@ -689,10 +689,12 @@
                     this.checkUnverifiedSendMessage(e, {force: true});
                 }.bind(this),
                 reject: function() {
-                    // do nothing
-                }
+                    this.focusMessageField();
+                }.bind(this)
             });
+
             this.$el.prepend(dialog.el);
+            dialog.focusCancel();
         },
 
         checkUnverifiedSendMessage: function(e, options) {
@@ -750,6 +752,8 @@
             var message = this.replace_colons(input.val()).trim();
             var convo = this.model;
 
+            this.focusMessageField();
+
             if (message.length > 0 || this.fileInput.hasFiles()) {
                 this.fileInput.getFiles().then(function(attachments) {
                     convo.sendMessage(message, attachments);