fix addmarker - extract mark from markdecorator

src/_pytest/nodes.py

@@ -173,10 +173,12 @@ class Node(object):
         chain.reverse()
         return chain
 
-    def add_marker(self, marker):
+    def add_marker(self, marker, append=True):
         """dynamically add a marker object to the node.
 
         :type marker: str or pytest.mark.*
+        ``append=True`` whether to append the marker,
+            if false insert at position 0
         """
         from _pytest.mark import MarkDecorator, MARK_GEN
 
@@ -185,7 +187,10 @@ class Node(object):
         elif not isinstance(marker, MarkDecorator):
             raise ValueError("is not a string or pytest.mark.* Marker")
         self.keywords[marker.name] = marker
-        self.own_markers.append(marker.mark)
+        if append:
+            self.own_markers.append(marker.mark)
+        else:
+            self.own_markers.insert(0, marker.mark)
 
     def iter_markers(self, name=None):
         """