Add ability to pan/zoom on the playermodel preview

[Jigoku]

Currently you can right click & drag the mouse to rotate the playerpreview in profile settings.

Adding support for zooming and panning, would help for players getting a closer look at their vanity options when customizing the character, and should also make it easier for people to tweak the models mdltrans / mdlyaw etc, without the need for setting bot vanities and launching a map.