Rename ol.layer.VectorEvent to ol.render.RenderEvent
Rename postrender to postcompose
Fire postcompose events from map
Add ol.render.DragBox
Use ol.render.DragBox in ol.interaction.DragZoom
Remove ol.control.DragBox
Move dispatchPostComposeEvent into base class
Rename getTransform to getImageTransform
Always dispatch postcompose event, even if no replay group
Factor out getTransform
Fire postcompose events for all layer types
Add frameState to postcompose event and minimise calls to getTransform
Add dynamic data example