Add support of a wheel button of a pointing device is rotated with the TranslateComposer under IE9-11.
Internet Explorer exposes the wheel event only via addEventListener, there is no onwheel attribute on DOM objects. So, the TranslateComposer was listening to a MouseWheelEvent (even if it supports the WheelEvent) which has no wheelDeltaX or wheelDeltaY properties under IE, just a property named wheelDelta. That property just allow us to determine the distance and direction that the wheel button has rolled.
Merge pull request #1507 from thibaultzanini/translate-composer-fix-IE

Add support for mouse wheel scrolling in TranslateComposer under IE9-11.