Log message:
Update devel/py-future to 0.16.0.

This release removes the configparser package as an alias for
ConfigParser on Py2 to improve compatibility with Lukasz Langa's
backported configparser package. Previously python-future and the
configparser backport clashed, causing various compatibility issues.

This releases also fixes these bugs:

- Fix newbytes constructor bug.
- Fix semantics of bool() with newobject.
- Fix standard_library.install_aliases() on PyPy.
- Fix assertRaises for pow and compile` on Python 3.5.
- Fix return argument of future.utils.ensure_new_type if conversion to
  new type does not exist.
- Add missing cmp_to_key for Py2.6.
- Allow the old_div fixer to be disabled.
- Improve compatibility with Google App Engine.
- Add some missing imports to the tkinter and tkinter.filedialog package
  namespaces.
- Fix raise_from on PY3 when the exception cannot be recreated from its
  repr.

Log message:
Import wip/py-future as devel/py-future.

future is the missing compatibility layer between Python 2 and Python 3.
It allows you to use a single, clean Python 3.x-compatible codebase to
support both Python 2 and Python 3 with minimal overhead.