qeditor: rework modified indicator, register tab names depend on content

Because Qt doesn't support QObject multiple inherance, it is a bit tricky
to have a base class which interact with the UI. The register tab name
now display:
- file dump name (for dumps)
- hwstub device path (for hwstub)
And the register editor display the filename
Change-Id: If2579992098c02627c67d560c824f1668e73bc45
Reviewed-on: http://gerrit.rockbox.org/979
Reviewed-by: Amaury Pouly <amaury.pouly@gmail.com>

utils/regtools/qeditor/regedit.h

@@ -226,9 +226,7 @@ public:
     RegEdit(Backend *backend, QWidget *parent = 0);
     ~RegEdit();
     virtual bool Quit();
-
-signals:
-    void OnModified(bool mod);
+    virtual QWidget *GetWidget();
 
 protected slots:
     void OnSocItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous);
@@ -267,6 +265,7 @@ protected:
     void CreateNewDeviceItem(QTreeWidgetItem *parent);
     void CreateNewRegisterItem(QTreeWidgetItem *parent);
     void CreateNewFieldItem(QTreeWidgetItem *parent);
+    void UpdateTabName();
 
     QGroupBox *m_file_group;
     QToolButton *m_file_open;