The root route example was the only using double quotes; switched it to single quotes for consistency

Load generators from both lib/rails/generators and lib/generators. Using the former since it's less obstrusive.

Generators load path now will be Ruby load path. If you want to use rspec:install generator, you need generators/rspec/install_generator in your load path.

Fix the documentation for root :to. It should use a fully qualified controller#action syntax (Closes #3606)