message: slack web api -> add blocks to sanitize options
diff: @@ -232,6 +232,14 @@ module.exports = function(bot, config) {
  bot.log.error('Could not parse attachments', err);
  }
  }
  + if (options.blocks && typeof(options.blocks) != 'string') {
  + try {
  + options.blocks = JSON.stringify(options.blocks);
  + } catch (err) {
  + delete options.blocks;
  + bot.log.error('Could not parse blocks', err);
  + }
  + }
  }
  