Get rid of ridiculous python2.5 shebang.

benchmark/autoencoder/aa.py

-#!/usr/bin/env python2.5
+#!/usr/bin/env python
 from __future__ import print_function
 from __future__ import absolute_import
 import numpy

benchmark/autoencoder/aa_numpy.py

-#!/usr/bin/env python2.5
+#!/usr/bin/env python
 from __future__ import print_function
 from __future__ import absolute_import
 import numpy as N