Apple's proprietary extensions are not supported

To parse files like below is not available.

```icloud.vcf
BEGIN:VCARD
VERSION:3.0
PRODID:-//Apple Inc.//iOS 11.2//EN
N:吉田;勇気;;;
FN:吉田勇気
X-PHONETIC-LAST-NAME:ヨシダ
item1.EMAIL;type=INTERNET;type=pref:worthmine@example.com
item1.X-ABLabel:_$!<Other>!$_
TEL;type=CELL;type=VOICE;type=pref:090xxxxyyyy
REV:2017-12-02T11:21:01Z
END:VCARD
```

I don't know well about them.