message: Removed reactPop tracking
  Was only needed for android activities - they can be destroyed when changing orientation so had to track if it was really popped in react (on android, pops have to come from react code). Don't need now only fragments because they're only destroyed when the app is closed
diff: @@ -17,7 +17,7 @@ class PopSync<T> extends React.Component<PopSyncProps<T>, any> {
  var items = prevItems
  .map(item => {
  var matchedItem = dataByKey[item.key];
  - var nextItem: any = {key: item.key, data: matchedItem || item.data, reactPop: !matchedItem};
  + var nextItem: any = {key: item.key, data: matchedItem || item.data};
  nextItem.index = !matchedItem ? item.index : matchedItem.index;
  return nextItem;
  })
  @@ -25,7 +25,7 @@ class PopSync<T> extends React.Component<PopSyncProps<T>, any> {
  .filter(item => !itemsByKey[getKey(item)])
  .map(item => {
  var index = dataByKey[getKey(item)].index;
  - return {key: getKey(item), data: item, index, reactPop: false};
  + return {key: getKey(item), data: item, index};
  })
  )
  .sort((a, b) => a.index !== b.index ? a.index - b.index : a.key.length - b.key.length);
  @@ -33,9 +33,6 @@ class PopSync<T> extends React.Component<PopSyncProps<T>, any> {
  }
  popNative(key: string) {
  this.setState(({items: prevItems}) => {
  - var poppedItem = prevItems.filter(item => item.key === key)[0];
  - if (Platform.OS === 'android' && !poppedItem.reactPop)
  - return null;
  var items = prevItems.filter(item => item.key !== key);
  return {items};
  });
  