Notify all listeners when the Cardoteka.reload method is called

[PackRuble]

Sequencing:

1. Save the value in SharedPreferences via native platforms
2. Call the SharedPreferences.reload method as required by documentation:

If you need to read a preference value that may have been changed by anything other than the SharedPreferences instance you are reading it from, you should call reload() on the instance before reading from it to update its cache with any external changes.

3. We expect watcher to notify all cards with new values (this doesn't happen)

[PackRuble]

It seems this would require implementing the notifyAll method, since we don't have access to the list of callbacks...

[PackRuble]

Related to #17