use separated class files, use hpp header extension, update include model

src/app/browser.hpp

@@ -0,0 +1,21 @@
+#ifndef APP_BROWSER_H
+#define APP_BROWSER_H
+
+#include <glibmm/i18n.h>
+#include <gtkmm/applicationwindow.h>
+
+namespace app
+{
+    class Browser : public Gtk::ApplicationWindow
+    {
+        public:
+
+            const char * TITLE = _("Yoda");
+            const int WIDTH = 640;
+            const int HEIGHT = 480;
+
+            Browser();
+    };
+}
+
+#endif // APP_BROWSER_H