Use default style function in FeatureOverlay
Fix the pointer index

It has to point to the end of the current block, not to the
beginning of the next block. See L581.
Merge pull request #1827 from elemoine/featureoverlay

Use default style function in FeatureOverlay
Merge pull request #1833 from ahocevar/hit-detection-pointer

Fix the pointer index
Add and export documentation for ol.render.canvas.Immediate
Merge pull request #1835 from pagameba/doc-canvas-immediate

Add and export documentation for ol.render.canvas.Immediate