[FEATURE REQUEST] call onSharedPreferenceChanged with a list of preference keys

[teqtic]

Sometimes I commit multiple preference keys at once. On the receiving listener end in another process, I sometimes need to receive the changes for all of these keys before acting on them. It would be really helpful if the sharedPreferenceChangeListeners would fire with a list of preference keys that were changed, if there were multiple, instead of one at a time.

P.S. Thank you for this library. If this is not a good place to request new features, please let me know!