Lazily require some heavy files

Library/Homebrew/cask/cmd/--cache.rb

Library/Homebrew/cask/cmd/audit.rb

Library/Homebrew/cask/cmd/doctor.rb

Library/Homebrew/cask/cmd/fetch.rb

Library/Homebrew/cask/cmd/info.rb

Library/Homebrew/cask/cmd/install.rb

Library/Homebrew/cask/cmd/internal_stanza.rb

Library/Homebrew/cask/cmd/reinstall.rb

Library/Homebrew/cask/cmd/uninstall.rb

Library/Homebrew/cask/cmd/upgrade.rb

Library/Homebrew/cli/named_args.rb

Library/Homebrew/cli/parser.rb

Library/Homebrew/dev-cmd/extract.rb

Library/Homebrew/extend/os/linux/extend/ENV/super.rb

Library/Homebrew/formulary.rb

Library/Homebrew/global.rb

Library/Homebrew/tap.rb

Library/Homebrew/test/cask/cmd/audit_spec.rb

Library/Homebrew/test/dev-cmd/extract_spec.rb

Library/Homebrew/test/support/helper/cask/install_helper.rb