Move IEditor::isTemporary to IDocument

It's a property of the document implementation, not of the specific
editor instance working on it.

Change-Id: I5c3dd054e21b646e2d94b891916a096d045923f8
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/android/androidmanifesteditor.cpp

@@ -73,11 +73,6 @@ Core::Id AndroidManifestEditor::id() const
     return Constants::ANDROID_MANIFEST_EDITOR_ID;
 }
 
-bool AndroidManifestEditor::isTemporary() const
-{
-    return false;
-}
-
 void AndroidManifestEditor::changeEditorPage(QAction *action)
 {
     AndroidManifestEditorWidget *editorWidget = static_cast<AndroidManifestEditorWidget *>(widget());

src/plugins/android/androidmanifesteditor.h

@@ -51,7 +51,6 @@ public:
     explicit AndroidManifestEditor(AndroidManifestEditorWidget *editorWidget);
 
     Core::Id id() const;
-    bool isTemporary() const;
 
 private slots:
     void changeEditorPage(QAction *action);