def entry(name)
      entry = @zip.find_entry(name)
      raise NotFoundError, "'#{name}'" if entry.nil?
      return entry
    end
def entry(name)
      entry = @zip.find_entry(name)
      raise NotFoundError, "'#{name}'" if entry.nil?
      return entry
    end
find and return zip entry with name
 @param [String] name file name in apk(fullpath)
 @return [Zip::ZipEntry] zip entry object
 @raise [NotFoundError] when 'name' doesn't exist in the apk