No xrange in Py3 #136

There is no xrange function in Python 3, but in out Python code in 3.x-slp:

anselm@Emmy:~/src/slp_ws/stackless36$ find Stackless -type f | xargs grep xrange
Stackless/test/taskspeed.py: xrange = range
Stackless/test/taskspeed.py: for i in xrange(0, n, 20):
Stackless/test/taskspeed.py: for i in xrange(0, n, 20):
Stackless/test/taskspeed.py: for i in xrange(0, n, 20):
Stackless/test/taskspeed.py: for i in xrange(0, n, 20):
Stackless/test/schedtest.py: for i in xrange(n):
Stackless/test/schedtest.py: for i in xrange(n):
Stackless/test/temptest.py: for i in xrange(0, n, 20):
Stackless/demo/counter.py: for i in xrange(n):
Stackless/demo/autoscheduling.py: for ii in xrange(1000):
Stackless/unittests/support.py: for i in xrange(len(objects)):

The fix is trivial.