Privatize emptyMemoryCache

[1ec5]

nitaliano/react-native-mapbox-gl#65 exposes -[MGLMapView emptyMemoryCache] to React Native users. Should this method even be public? I see that it’s used in iosapp’s gear menu, as a way of simulating low memory conditions. However, it doesn’t seem to have a good use case beyond that, and it’s poorly named to boot.

/cc @bsudekum @incanus

[incanus]

No, this is not meant for public consumption.

[1ec5]

Because this is public API, it needs to be deprecated before it can be removed. If it’s still useful in iosapp, then it should be redeclared via a category on MGLMapView and looked at askance.