def create_pikelets(pikelets_data = {})
      pikelets_data.inject([]) do |memo, (type, cfg)|
        pikelets = Flapjack::Pikelet.create(type, @shutdown, :config => cfg,
                                            :boot_time => @boot_time)
        memo += pikelets
        memo
      end
    end
passed a hash with {PIKELET_TYPE => PIKELET_CFG, ...}
returns unstarted pikelet instances.