Microsoft Outlook headers not being detected in replies

Although https://github.com/github/email_reply_parser/pull/54 seems to fix one type of Outlook email reply, one with a quoted body, I don't believe that the following example reply from an Outlook mail client is currently working:

```
Outlook email reply with a team mention in the email body.

From: CRM Comments [crm-comment@example.com]
Sent: Friday, 23 March 2012 5:08 p.m.
To: John S. Greene
Cc: Jane Q. Codes
Subject: Re: [@organization/team] Discussion about mail replies. (#1)

Should the team mention from the subject line be parsed in the comment?

> Here is quoted text.
>
```

I've pushed up a test via https://github.com/github/email_reply_parser/commit/33ccba0a4b15a60db42bdbec56a9d6cb783ed6db that fails locally on the example fixture (pushed in https://github.com/github/email_reply_parser/commit/51639404b4e14eeba934d11bd77837136efdeab9).

In the example here, I believe only the following string should be returned:

```
Outlook email reply with a team mention in the email body.
```