def create(&block)
      register
      self.instance_eval(&block) if block_given?
      content = self.to_ruby
      fullpath = File.join(self.class.bindir, filename)
      #puts "creating double: #{fullpath} with content:\n#{content}" # debug
      f = File.open(fullpath, 'w')
      f.puts content
      f.close
      FileUtils.chmod(0755, File.join(self.class.bindir, filename))
      self
    end
def create(&block)
      register
      self.instance_eval(&block) if block_given?
      content = self.to_ruby
      fullpath = File.join(self.class.bindir, filename)
      #puts "creating double: #{fullpath} with content:\n#{content}" # debug
      f = File.open(fullpath, 'w')
      f.puts content
      f.close
      FileUtils.chmod(0755, File.join(self.class.bindir, filename))
      self
    end
Create the executable double.

 @return [String] full path to the double.