added badges to readme
removed unused columns from the dataset (stored in the response_set)
protect dataset attributes from mass assignment
redirect to user to dashboard on start_questionnaire error rather than dataset
refactored start_questionnaire slightly, removed unreachable redirect, trimmed down code slightly
corrected dataset user assignment
added stub questionnaire for easier testing
added note about GB stub version
Merge remote-tracking branch 'origin' into code-maintainence

Conflicts:
	db/schema.rb
Merge remote-tracking branch 'origin' into code-maintainence

Conflicts:
	db/schema.rb
schema update
added documentation_url back to the dataset
trigger documentation_url to be assigned for all datasets
removed unnecessary 'and return'
Merge pull request #427 from theodi/code-maintainence

Code Maintainence