[Feature Request] Support zooming or changing the icon size

[rhaberkorn]

The fixed icon size can be very small on high resolution displays, especially for the thumbnails. It would be cool, if we could increase the icon size and give more space to the thumbnails.

I guess that you don't want to support vector/SVG icons - and that's great - you should avoid code bloat. However, a simple linear interpolation of the pixbufs would suffice. Or even simpler: don't scale the XPM icons at all but just increase the grid spacing, giving thumbnails more space.