Put PYTHONPATH Manager paths at the front of sys.path rather than ins…

…erting at position 1.

Was the intention to always have the current working directory ('') at position 0? Because it was not at position 0.

spyder/app/mainwindow.py

@@ -1748,7 +1748,8 @@ def update_python_path(self, new_path_dict):
 
         for path, active in reversed(new_path_dict_p.items()):
             if active:
-                sys.path.insert(1, path)
+                # TODO: should cwd ('') always be at front?
+                sys.path.insert(0, path)
 
         # Any plugin that needs to do some work based on this signal should
         # connect to it on plugin registration