mat-select model don't update after removing options programmatically

#### Bug, feature request, or proposal:
Bug

#### What is the expected behavior?
I expect to get the model updated and the change event called after remove selected options of the options list.

#### What is the current behavior?
The model don't update and the change event is not called, but visually is updated.

#### What are the steps to reproduce?
1 - http://plnkr.co/edit/RNAeZbaNrtMQRrjC7IDc?p=preview ;
2 - Click on "Remove options";
3 - mat-select visually update;
4 - model dont update and change event is not called;

#### What is the use-case or motivation for changing an existing behavior?
If I change the options for any reason, I expect to get the change events and the model to be updated in order to keep data consistent;

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
master

#### Is there anything else we should know?
No

リンクされたPlunkerの再現と、オプションがプログラムによって削除されたときのmat-selectの動作から始めます。「Remove options」をクリックした後に、選択されたモデルとchange eventがどのように反応するかを追跡します。完了条件は、モデルが更新され、視覚的な選択内容に一致するようにchange eventが発行されることです。

索引モデルが issue の本文から書いたものです。