code: function addStepToBlock(that, block, stepId, stageId, positions) {
          var stepInBlock;
          // Add step, if not already added.
          if (block.hasItem(stepId)) return false;
  
          stepInBlock = {
              type: stageId,
              item: stepId,
              id: stepId
          };
  
          if (isDefaultStep(that.steps[stepId])) {
              makeDefaultStep(stepInBlock);
          }
          block.add(stepInBlock, positions);
          return true;
      }
docs: #### addStepToBlock
  
  Adds a step to a block
  
  Checks if a step with the same id was already added.
  
  @param {object} that Reference to Stager object
  @param {object} stage The block object
  @param {string} stepId The id of the step
  @param {string} stageId The id of the stage the step belongs to
  @param {string|number} positions Optional. Positions allowed for
  step in the block
  
  @return {boolean} TRUE if the step is added to the block