Add timed items

For #9
Change news edition to article

for #9
Add timed item to formats list
Change TimedEdition#closes_at to end_date
Add creative work model

For #9
Add organization edition

For #9
Change article rendering app to www
Add JobEdition class

For #9
Add FaqEdition

For #9
Add CaseStudyEdition

for #9
Slim down course model

For #9
Add course instance model

Needs more complete tests before being finished
Merge pull request #11 from theodi/timed-items

Add timed items
Merge branch 'article-editions' of git://github.com/theodi/odi_content_models

Conflicts:
	app/decorators/models/artefact_decorator.rb
	lib/odi_content_models/test_helpers/factories.rb
Merge pull request #12 from theodi/article-editions

Change news edition to article
Merge pull request #13 from theodi/case-study-edition

Add CaseStudyEdition
Require attachable with metadata

Works fine locally, but explodes in Jenkins
Merge branch 'master' of github.com:theodi/odi_content_models
Merge branch 'faq-edition' of github.com:theodi/odi_content_models

Conflicts:
	app/decorators/models/artefact_decorator.rb
Merge pull request #14 from theodi/faq-edition

Add FaqEdition