def run_container(image, data, &block)
      unless @prestart && @container
        create_container(image)
        start_container
      end

      begin
        attach_container(data, &block)
      ensure
        wait_container
        delete_container
        if @prestart
          create_container(image)
          start_container
        end
      end
      nil
    end
Public: Create and start a Docker container if one hasn't been started
already, then attach to it its stdin/stdout.

image    - The image to run.
data     - The data to pipe to the container's stdin.

Returns the data from the container's stdout.