python3: 'jinja2.utils.Cycler object' has no attribute 'next'

[iffy]

The jinja2.utils.Cycler object no longer has a next() method in Python 3:

Running the following with Python 3:

from jinja2 import Environment

env = Environment()
t = env.from_string('''
{% set a = cycler('odd', 'even') %}
{{ a.next() }}
{{ a.next() }}
''')
result = t.render()
print(result)

Results in this error:

Traceback (most recent call last):
  File "example.py", line 9, in <module>
    result = t.render()
  File "/private/tmp/a/py3/lib/python3.4/site-packages/jinja2/environment.py", line 989, in render
    return self.environment.handle_exception(exc_info, True)
  File "/private/tmp/a/py3/lib/python3.4/site-packages/jinja2/environment.py", line 754, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/private/tmp/a/py3/lib/python3.4/site-packages/jinja2/_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "<template>", line 3, in top-level template code
jinja2.exceptions.UndefinedError: 'jinja2.utils.Cycler object' has no attribute 'next'

I'm going to work around this by adding the new built-in next() function as an environment global.

[ThiefMaster]

dup of #474 and there's a PR #493 but the author apparently never updated it with my suggestions...