Add the travere_parents function to a utility directory

jedi/common/utils.py

@@ -0,0 +1,12 @@
+import os
+
+
+def traverse_parents(path, include_current=False):
+    if not include_current:
+        path = os.path.dirname(path)
+
+    previous = None
+    while previous != path:
+        yield path
+        previous = path
+        path = os.path.dirname(path)