Don't store num color components in pixel traits
Don't store num color components in pixel traits

This is redundantly stored in pixel_format_info
TODO: (somehow) consolidate pixel_traits and pixel_format_info

ukoeln-vis/ctpperf,szellmann/visionaray,tu500/visionaray,ukoeln-vis/ctpperf,tu500/visionaray,szellmann/visionaray