Move IEditor::createNew to IDocument::setContents

The method is for setting the contents, so it belongs to the document,
and should be named correspondingly.

Change-Id: I40363dc08f11268f530885b512e4a88e8b10d096
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/diffeditor/diffeditor.h

@@ -60,7 +60,6 @@ public:
     void clear(const QString &message);
 
     // Core::IEditor
-    bool createNew(const QString &contents);
     bool open(QString *errorString, const QString &fileName, const QString &realFileName);
     Core::IDocument *document();
     Core::Id id() const;