RuboCop Style/StringLiterals rule
RuboCop rules fix

Cleaning auto-generated spec_helper.rb, .gemspec and Guardfile files
RuboCop fixes

Metrics/AbcSize and Metrics/CyclomaticComplexity rules were auto-fixed
by fixing other rules
RuboCop Metrics/ParameterLists exclusions

Moving permanent rule into default .rubocop.yml