revamped undo system in preparation for marker support

dialogs/newsequencedialog.cpp

@@ -62,9 +62,9 @@ void NewSequenceDialog::on_buttonBox_accepted()
 	s->audio_frequency = ui->audio_frequency_combobox->currentData().toInt();
 	s->audio_layout = AV_CH_LAYOUT_STEREO;
 
-    TimelineAction* ta = new TimelineAction();
-    panel_project->new_sequence(ta, s, true, NULL);
-    undo_stack.push(ta);
+    ComboAction* ca = new ComboAction();
+    panel_project->new_sequence(ca, s, true, NULL);
+    undo_stack.push(ca);
 }
 
 void NewSequenceDialog::on_comboBox_currentIndexChanged(int index)

dialogs/replaceclipmediadialog.cpp

@@ -83,8 +83,8 @@ void ReplaceClipMediaDialog::replace() {
 							use_same_media_in_points->isChecked()
 						);
 
-				for (int i=0;i<sequence->clip_count();i++) {
-					Clip* c = sequence->get_clip(i);
+                for (int i=0;i<sequence->clips.size();i++) {
+                    Clip* c = sequence->clips.at(i);
 					if (c != NULL && c->media == old_media) {
 						rcmc->clips.append(c);
 					}