change ForeignKey to ManyToManyField on QuerySet channel field
generate migration del channel ForeignKey add channel ManyToManyField
update changelog
rewrite rules to seek channels in queryset
fake teste queryset on save
Fix pep8
used param -s on nose run tests
fixed boxes queryset tests
update boxes migration 0006
Merge branch 'stable/0.2.x' of github.com:opps/opps into container_queryset_multchannel
merge draft version, @jeanmask

* 'stable/0.2.x' of github.com:opps/opps:
  Improve pivot model of Container related.
  Update grappelli to ver. 2.4.12
  Improve opps.containers admin.
  Refact related post to containers migration.

Conflicts:
	CHANGELOG.rst
Merge pull request #414 from opps/container_queryset_multchannel

Container queryset multchannel