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
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
Snapshot