Handling of NSUID

The following _base64 encoded_ binary plist:

```
YnBsaXN0MDDRAQJTZm9vgAEICw8AAAAAAAABAQAAAAAAAAADAAAAAAAAAAAAAAAAAAAAEQ==
```

is parsed as

```
{ foo: 1 }
```

while [plistutil](http://www.libimobiledevice.org/) parses it as

```
<dict>
    <key>foo</key>
    <dict>
        <key>CF$UID</key>
        <integer>1</integer>
    </dict>
</dict>
```
