Merge pull request #355 from mauler/feature-opps-menu-improvement

Adds OPPS_MENU_ONLY_WITH_PUBLISHED_CONTAINERS
set new develop version Opps 0.2.x to 0.2.7
Merge branch 'stable/0.2.x' of github.com:opps/opps into improvement-container_tags

Conflicts:
	docs/configuration/core.md
Merge pull request #367 from mauler/improvement-container_tags

Improvement container tags
Update README.rst
Add manager command to export containerboxes data
fix pep8
change Channels to Channel
Merge pull request #369 from campusparty/stable/0.2.x

Add manager command to export containerboxes data
Fixes for python 2.6 compatibility
Adds main_image foreign key to channel
Merge pull request #370 from mauler/feature-py26

Fixes for python 2.6 compatibility
Merge pull request #371 from mauler/feature-channel-main_image

Adds main_image foreign key to channel
run test in python 2.6 and 2.7
Fix Channel migration
Removes python 2.6 travis tests
Adds ContainerManager and ContainerQueryset

With these two classes it's possible to call manager methods on
reverse related for example:

{{ channel.container_set.all_published }}
Merge branch 'feature-container-manager' into sandbox

Conflicts:
	docs/configuration/core.md
	opps/channels/migrations/0005_auto__add_field_channel_main_image.py