[new compiler] Fix support for namespaces in attached properties

When doing
    import QtQml 2.0 as MyQml
with
    MyQml.Component.onComplete: ...

We now store "MyQml.Component" as one string as the type name, in order to get
resolved correctly.

Change-Id: I11a6def88bcb8b98b5fa9548053e27fb58170e62
Reviewed-by: Lars Knoll <lars.knoll@digia.com>