remove unused API (and ifstream)

libs/gtkmm2ext/gtkmm2ext/textviewer.h

@@ -46,7 +46,6 @@ class LIBGTKMM2EXT_API TextViewer : public Gtk::Window, public Transmitter
 	Gtk::TextView& text()         { return etext; }
 	Gtk::Button& dismiss_button() { return dismiss; }
 
-	void insert_file (const std::string &);
 	void scroll_to_bottom ();
 
 	void deliver ();

libs/gtkmm2ext/textviewer.cc

@@ -73,32 +73,6 @@ TextViewer::signal_released_handler()
 	hide();
 }
 
-void
-TextViewer::insert_file (const string &path)
-
-{
-	char buf[1024];
-	ifstream f (path.c_str());
-
-	if (!f) {
-		return;
-	}
-
-	Glib::RefPtr<Gtk::TextBuffer> tb (etext.get_buffer());
-
-	tb->begin_user_action();
-	while (f) {
-		f.read (buf, sizeof (buf));
-
-		if (f.gcount()) {
-			buf[f.gcount()] = '\0';
-			string foo (buf);
-			tb->insert (tb->end(), foo);
-		}
-	}
-	tb->end_user_action();
-}
-
 void
 TextViewer::scroll_to_bottom ()