CBF: find difference between user and pterodon map

[sonicpp]

During downloading a map, sometimes it shows "downloading Pterodon map" instead of "user map". This is for VC RedDawn maps (*vcrd.cbf). These maps have CBF part only (as opposite to user maps with also DAT part), and all are "CLASSIC" files (some user maps are CLASSIC as well). So far, it looks like the difference between Pterodon map and user map is by CBF content (some file) instead of structure of CBF file.