create certificate on completion of response_set
added link to certificate from dataset page
added basic guard-test as a development dependency
set attained level on certificate from response_set
allow certificates to be viewed
restructured so that certificate is created from the response_set
Merge pull request #99 from theodi/certificate-creation

Certificate creation
Merge branch 'master' into copying_response_sets

Conflicts:
	app/models/response_set.rb
	test/unit/response_set_test.rb
Merge branch 'master' into copying_response_sets

Conflicts:
	app/models/response_set.rb
	test/unit/response_set_test.rb