Convert point annotations to RTree instead of pre-creating tiles for all zoom levels

[kkaefer]

depends on #1695

[kkaefer]

@incanus, is there any reason we're using integer IDs rather than wrapping a shared_ptr to track annotations for later removal?

[incanus]

is there any reason we're using integer IDs rather than wrapping a shared_ptr to track annotations for later removal?

If annotation adds/removes are synchronous, why bother with the complexity? basically

See also how we map them Cocoa-side, which I suppose could be adapted to live pointers:

mapbox-gl-native/platform/ios/MGLMapView.mm

Line 79 in cfee5aa

@property (nonatomic) NSMapTable *annotationIDsByAnnotation;

[kkaefer]

why bother with the complexity? basically

We need to maintain a separate mapping of ID to Annotation so we can remove the correct elements from the RTree.

[kkaefer]

@incanus can you review please?

[incanus]

We're not hitting this as part of b3.

[jfirebaugh]

⇢ #2673