Repair should handle adding UID when missing

When exporting from Apple's Address Book, I get a number of vCards without a UID and repair should handle this.

**Export from Address Book**
```
BEGIN:VCARD
VERSION:3.0
PRODID:-//Apple Inc.//Mac OS X 10.10.1//EN
N:Test;Stephanie;;;
FN:Stephanie Test
ORG:Testing Magazine;
TITLE:Photo Editor
EMAIL;type=INTERNET;type=WORK;type=pref:Stephanie.Test@test.com
TEL;type=WORK;type=VOICE;type=pref:+1-555-555-5555
ADR;type=WORK;type=pref:;;123 Testing Drive;Bristol;FL;55555;
X-ABUID:43D00A4F-8DBE-4B64-A617-7AA0C9524367
END:VCARD
```

**Validation gives an error, which it should**
```
[ERROR] UID MUST appear exactly once in a VCARD component
```

But when running repair on his file, it doesn't fix this issue.