ArticlePkg: tickets and attempts are displayed as list of resource uri
Tickets: comments as a list of {author, message, date}.
Changed add_meta to format_response. Because it formats the response: adding resource uri, but only if there is a list of objects, it also adds meta.
Changed content of add_resource_uri. Previously it added resouces uri to one object or to a list of objects, but now it adds resources uri to an object.
Adjustments in test_renderer
appending checkin and validations (which are Checkpoint) to Attempt.
Adding checkin and validation to Attempt.to_dict(). #133
Clean unnecessary comments
Ajustes de acordo com comentarios de revisão
Merge branch 'master' of git://github.com/scieloorg/balaio into 133_related_resources

Conflicts:
	balaio/renderers.py
	balaio/tests/test_renderer.py
total_count to total in docs.
Fixes tests which were not OK
Troca de _N() por _positive_int_or_zero() (#142)
Merge branch 'master' of git://github.com/scieloorg/balaio into 133_related_resources

Conflicts:
	balaio/gateway_server.py
	balaio/renderers.py
	balaio/tests/test_renderer.py
Merge pull request #138 from robertatakenaka/133_related_resources

ufa!