SetPositioning exposition in the API

The method in ol.Overlay is not exposed whereas is equivalent
getter getPositioning is visible in API and documentation.
The PR add a line of description to the documentation and expose
the method
Add script to combine examples
Add target to concatenate and build all examples
Only build combined examples in integration tests
Use getPixel function instead of offset from event
Merge pull request #1119 from fredj/drz_offset

Use getPixel function instead of offset from event
Add stopEvent option in ol.OverlayOptions typedef
Add new container which don't stop event propagation

and allow overlays to optionnally stop event propagation
Adjust event propagation for overlay example
Adjust event propagation for popup example
Fix indent
Merge pull request #1121 from bbinet/fix-whitespace-indent

Fix indent
Add controls to ol-overlaycontainer-stopevent

so that events won't be propagated to the map when interacting with a control
Merge pull request #1120 from bbinet/overlay-stop-events

Configurable event propagation for overlays
Typo crossOriin => crossOrigin
Merge pull request #1126 from kryger/patch-1

Typo crossOriin => crossOrigin.
Add ol.Map#getEventPixel
Add ol.Map#getEventCoordinate
Rename offset* attributes to delta*
Export ol.Map#getEventPixel