support .skin files for models (modelname_<n>.skin) like Q3A and DP
TBH no idea. Maybe this was only DarkPlaces and I was wrong about Q3A - may have looked in a Q3A related mod.
It certainly was primarily targeted at DP skin support. Isn't that correct? From looking at DP code it does use %s_%i.skin. I may have been wrong about that originating from Q3.
DP-emphasized version looks legit. Q3 way is easy to handle along with this by int->string change.
Still interested, if this ever worked, because code got a few edits, while trying to load invalid
path/model.md3_<n>.skinall this time.
(Actually dicovered this code, because people were getting string overflow and loading+parsing model file instead of .skin.)