Prevent symbol clashes for qml classes

Fix namespace usage such that all classes in shared/qml live in the
Qml namespace, and classes in QmlDesigner plugin in the QmlDesigner
namespace.

This should prevent any symbol clashes until we can finally get rid
of the file dublicates (e.g. QmlDocument).

src/plugins/qmleditor/qmlmodelmanagerinterface.h

@@ -39,9 +39,13 @@
 #include <qml/qmldocument.h>
 #include <qml/metatype/qmltypesystem.h>
 
-namespace QmlEditor {
 
+namespace Qml {
 class Snapshot;
+}
+
+
+namespace QmlEditor {
 
 class QMLEDITOR_EXPORT QmlModelManagerInterface: public QObject
 {
@@ -51,11 +55,11 @@ public:
     QmlModelManagerInterface(QObject *parent = 0);
     virtual ~QmlModelManagerInterface();
 
-    virtual Snapshot snapshot() const = 0;
+    virtual Qml::Snapshot snapshot() const = 0;
     virtual void updateSourceFiles(const QStringList &files) = 0;
 
 signals:
-    void documentUpdated(QmlEditor::QmlDocument::Ptr doc);
+    void documentUpdated(Qml::QmlDocument::Ptr doc);
 };
 
 }