Remove ol.structs.RBush#forEach function
Use goog.iter.toArray instead of ol.structs.RBush#forEachInExtent
Use goog.iter.forEach instead of ol.structs.RBush#forEachInExtent
Use iterator in ol.source.Vector#forEachFeatureAtCoordinate
Use iterator in ol.source.Vector#forEachFeatureInExtent

The function now behaves like a real forEach (ignores the callback return value)
Remove ol.structs.RBush#forEachInExtent function