Fix sytle issues in Mutant::Differ
Fix style issue in Printer::Config
Fix style issue in Mutant::CLI*
Fix style issues in Mutant::Reporter*
Fix style issues in Mutant::Mutantion*
Fix style issues in Mutant::Subject
Fix style issues in Mutant::Mutator
Fix style issues in Mutant::Loader
Fix style issues in Killer::Rspec
Fix style in Mutant::Zombifier
Fix style in Mutant::Killer
Fix style issues in Mutant::NodeHelpers
Fix style issues in Mutant::CLI
Fix stlye in Mutant::Matcher::Methods
Fix style in Mutant::Matcher::Method::Instance
Fix style in Mutant::Matcher::Method
Fix style in Mutant::Matcher::Method::Singleton
Fix style in Mutant::Color
Fix all style warnings under spec/**/*.rb