Move future import to the top

All from __future__ imports have to be at the top of the file.
Merge pull request #338 from cXhristian/future-import-fix

Move future import to the top of the file
pep8
ignore wiki/attachments for now as it occurs from running tests and should not be distributed
initial tests for custom queryset methods
do not call get_empty_query_set, that's deprecated
add tests of none() and empty queryset functionality
Merge pull request #337 from fsx999/master

python_2_unicode_compatible decorateur
use gettext_lazy where appropriate, thanks @jluttine for starting work on this
add more tests of custom managers and add support for django 1.5 and 1.6's patterns for empty querysets
Fix #263 and style article list header
Fix #341
@python_2_unicode_compatible
@python_2_unicode_compatible