#12323 mousewheel

**Cross OS & web browsers testing**

ticket http://trac.openmicroscopy.org/ome/ticket/12323

For some reason PanoJS has that off on Mac
```
// The dafault is to pan with wheel events on a mac and zoom on other systems
PanoJS.USE_WHEEL_FOR_ZOOM = (navigator.userAgent.indexOf("Mac OS X")>0 ? false: true);
```
I cannot find any explanations why, but this PR should unify it.