Refactor `CLI::Zap`.

Library/Homebrew/cask/lib/hbc/cli/zap.rb

@@ -2,9 +2,16 @@ module Hbc
   class CLI
     class Zap < Base
       def self.run(*args)
-        cask_tokens = cask_tokens_from(args)
-        raise CaskUnspecifiedError if cask_tokens.empty?
-        cask_tokens.each do |cask_token|
+        new(*args).run
+      end
+
+      def initialize(*args)
+        @cask_tokens = self.class.cask_tokens_from(args)
+        raise CaskUnspecifiedError if @cask_tokens.empty?
+      end
+
+      def run
+        @cask_tokens.each do |cask_token|
           odebug "Zapping Cask #{cask_token}"
           cask = CaskLoader.load(cask_token)
           Installer.new(cask).zap