Eventhough some of us sentimentals still like the syntax `to_not` the current trend is to move to the new syntax `not_to`. In this commit we are updating the references of expectations that used `to_not` to `not_to`.
Both avoiding 'should' and repiting 'it' on the tests description improves reading them and also makes all descriptions consistent. Read about cop at http://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/ExampleWording
