code: function unload() {
      u.each(opts.sources, function(source) {
        if (source.src && source.src.unref) { source.src.unref(); }
        if (source.cache && source.cache.unref) { source.cache.unref(); }
      });
      u.each(opts.outputs, function(output) {
        if (output.output && output.output.cancel) { output.output.cancel(); }
      });
      if (generator.reload && generator.reload.cancel) { generator.reload.cancel(); }
      if (generator.clientSave && generator.clientSave.cancel) { generator.clientSave.cancel(); }
    }
docs: disconnect all sources and cancel all throttled functions