Stop exporting getTransformFromProjections and transformWithProjections
Add tilePixelRatio option to ol.source.Tile
Add tilePixelRatio option to ol.source.TileImage
Add tilePixelRatio option to ol.source.WMTS
Add example
Use tilePixelOption in wmts-hidpi example
Add an offset property to ol.Overlay

Replaces "offsetX" and "offsetY" by an ol.Object "offset" property.
Merge pull request #2214 from probins/patch-2

Stop exporting getTransformFromProjections and transformWithProjections
Allow the value to be changed while iterating over the rtree
Remove the unused popup from the synthetic-points example
Add docs for tilePixelRatio
Merge pull request #2216 from elemoine/pixelratio

Add tilePixelRatio option to ol.source.WMTS
Merge pull request #2220 from fredj/synthetic-points-popup

Remove the unused popup from the synthetic-points example
Better docs for ol.Overlay#positioning
Make ol.Overlay always call setOffset
Make ol.Overlay always call setPositioning
Merge pull request #2219 from fredj/rbush-update

Allow the value to be changed while iterating over the rtree
Merge pull request #2217 from elemoine/overlay-offset

Add an offset property to ol.Overlay
Add ol.structs.RBush#getIterator function
Check if the tree is changed between iterator.next