getCurrStep = function getCurrStep() {
      var step;

      if (!currTour || currStepNum < 0 || currStepNum >= currTour.steps.length) {
        step = null;
      } else {
        step = currTour.steps[currStepNum];
      }

      return step;
    }
getCurrStep

@private
@returns {Object} the step object corresponding to the current value of currStepNum