adding sequences can now be undone

dialogs/newsequencedialog.cpp

@@ -4,6 +4,7 @@
 #include "panels/panels.h"
 #include "panels/project.h"
 #include "project/sequence.h"
+#include "project/undo.h"
 
 #include <QVariant>
 #include <QDebug>
@@ -61,7 +62,9 @@ void NewSequenceDialog::on_buttonBox_accepted()
 	s->audio_frequency = ui->audio_frequency_combobox->currentData().toInt();
 	s->audio_layout = AV_CH_LAYOUT_STEREO;
 
-    panel_project->new_sequence(s, true, NULL);
+    TimelineAction* ta = new TimelineAction();
+    panel_project->new_sequence(ta, s, true, NULL);
+    undo_stack.push(ta);
 }
 
 void NewSequenceDialog::on_comboBox_currentIndexChanged(int index)