code: function changeState ( item, type, cb) {
      var i
      switch (type) {
      case 'add':
        my.state.trackedfiles[item] = true;
        break
      case 'rm':
        for (i in my.state.trackedfiles) {
          if (path.basename(i) === path.basename(item)) {
            delete my.state.trackedfiles[i];
          }
        }
        break
      default:
        throw new Error('Wrong arguments for function changeState')
      }
      return cb(null)
    }
docs: end checkState  ## CHANGESTATE ## Modifies the private variable my.state. Used in async.chain which takes a callback with single error argument.