Metadata fixes

Fix remaining references to PSF license, change maintainer info.
Removed most occurances of __author__, since it felt redundant
with the copyright notice (credit) and package metadata
(developer contact).

Also fixed references to Python 2.3 (it's not even tested anymore)
and changed calls from python3 to just python (let the system decide).
diff --git a/sandbox/scheduler.py b/sandbox/scheduler.py
index 39740eb..62794d5 100644
--- a/sandbox/scheduler.py
+++ b/sandbox/scheduler.py
@@ -1,11 +1,12 @@
+# -*- coding: utf-8 -*-
 """
 Copyright (c) 2003-2005  Gustavo Niemeyer <gustavo@niemeyer.net>
 
-This module offers extensions to the standard python 2.3+
+This module offers extensions to the standard Python
 datetime module.
 """
-__author__ = "Gustavo Niemeyer <gustavo@niemeyer.net>"
-__license__ = "PSF License"
+__author__ = "Tomi Pieviläinen <tomi.pievilainen@iki.fi>"
+__license__ = "Simplified BSD"
 
 import datetime
 import _thread