Add respond_to blocks to controller methods

Stops 500 errors when accept headers explicitly sent
Override high_voltage to add respond_to block
Add middleware to send Content-Location header
Merge branch 'master' of github.com:theodi/open-data-certificate into feature-content-negotiation

Conflicts:
	config/application.rb
We don't need you middleware
Add alternate_rails gem
Add before_filter hook to load alternate_rails stuff
Merge pull request #489 from theodi/feature-content-negotiation

Fix content negotiation issues