ported seekablewidget to timebasedview

Cuts down on a lot of code duplication and opens up usage of the new TimelineViewSelectionManager framework

app/node/project/serializer/serializer210907.cpp

@@ -20,6 +20,7 @@
 
 #include "serializer210907.h"
 
+#include "config/config.h"
 #include "node/factory.h"
 
 namespace olive {
@@ -596,7 +597,7 @@ void ProjectSerializer210907::LoadMarkerList(QXmlStreamReader *reader, TimelineM
         }
       }
 
-      markers->AddMarker(TimeRange(in, out), name);
+      new TimelineMarker(Config::Current()[QStringLiteral("MarkerColor")].toInt(), TimeRange(in, out), name, markers);
     }
 
     reader->skipCurrentElement();