Upgrade closure-library and closure-util version
Add missing goog.require
Remove mousewheel event name workaround

Fixed upstream https://github.com/google/closure-library/pull/308
Set goog.array.ASSUME_NATIVE_FUNCTIONS to true
Remove Google Maps example
Merge pull request #2711 from elemoine/remove-gmaps-example

Remove Google Maps example
Merge pull request #2549 from fredj/assume-array-native

Use goog.array.ASSUME_NATIVE_FUNCTIONS define
Merge pull request #2647 from fredj/closure-lib-upgrade

Upgrade closure library version
Set the opacity directly to element.style.opacity

goog.style.setOpacity handles the IE8 case (but we are doing the same
above in the same function) and Firefox prior to version 3.5 (latest
stable release in April 2011).

See https://developer.mozilla.org/en-US/docs/Web/CSS/opacity
Merge pull request #2714 from fredj/opacity

Set the opacity directly to element.style.opacity
Add an EPSG:3857 map to Tissot example
Merge pull request #2715 from elemoine/tissot

Add an EPSG:3857 map to Tissot example
Change the control visibility by using css class

Instead of changing the button opacity in the control, only add/remove
a css class (ol-hidden). This let the developer easily change the
behavior by updating the css.
Merge pull request #2717 from fredj/rotate-css

Change the control visibility by using css class
Consistent circle transform

Depending on compilation flags, applying a transform used to either:
- work;
- fail throwing an abstract method not implemented message;
- fail silently.

Now it should consistently work, like the other geometries.

Adding a polygon factory method creating an approximation of a circle on
a plane would be useful for users wanting the circle to be deformed.
It would be similar to the `circular` function which creates an
approximation of a circle on a sphere.
Merge pull request #2696 from gberaudo/consistent_circle_transform

Consistent circle transform.
Make ol.Map#setView do not accept undefined

With this change map.setView(null) is permitted, but map.setView(undefined) is not. map.getView now always returns a defined value, which may be null is setView was called with null.
Add ol.extent.forEachCorner
Add ol.extent.containsXY
Add ol.geom.flat.segments.forEach