API: temporaryEditor --> isTemporary

Reviewed-by: Daniel Molkentin <daniel.molkentin@nokia.com>

src/plugins/texteditor/plaintexteditor.h

@@ -47,7 +47,7 @@ public:
     bool duplicateSupported() const { return true; }
     Core::IEditor *duplicate(QWidget *parent);
     const char *kind() const;
-    bool temporaryEditor() const { return false; }
+    bool isTemporary() const { return false; }
 private:
     QList<int> m_context;
 };