Entities ignored in XML.loadString

```scala
val xmlLs = scala.xml.XML.loadString( "<a>ceci &amp; un msg</a>" )
```

Gives me an element with only one child of type scala.xml.Text.

Where as
```scala
val xmlCode = <a>ceci &amp; un msg</a>
```

Gives me an element with 3 children. The second is an scala.xml.EntityRef :
```scala
xmlCode.child(1).getClass
```

Then of course i have
```scala
xmlLs != xmlCode
```