Fix OBJ rendering in software renderers, and other things

Pass surf->vbStart to SetupFrame instead of 0, and pass 0 to DrawArrays instead of surf->vbStart.

Use a potentially faster method of modifying the OBJ file text buffer by modifying it directly.

Add RealignVector and FixUV methods to begin work on re-aligning OBJ models to the same orientation as MD3 models.

Re-align OBJ models to match MD3 models

Fix normal calculation for re-aligned OBJs

Ensure AddSkins does not go out of bounds of surfaceskinIDs

Do not precache skins that were replaced by the user.

Fix OBJs with a large number of materials not being fully rendered

Print a warning message if a material referenced by the OBJ could not be found.

Free surface triangles once they are no longer needed

Also, use continue instead of return so that surfaces after those with missing materials are still rendered.

Fail if a face side has no vertex reference. Vertex references are required for a valid OBJ.

Clean up OBJ model code

Remove commented code, mainly Printf's that aren't used any more.

Add more documentation comments, and tweak existing documentation comments

Replace ParseVector2 and ParseVector3 with a template ParseVector function

src/r_data/models/models.cpp

@@ -942,3 +942,4 @@ bool IsHUDModelForPlayerAvailable (player_t * player)
 	FSpriteModelFrame *smf = FindModelFrame(player->ReadyWeapon->GetClass(), state->sprite, state->GetFrame(), false);
 	return ( smf != nullptr );
 }
+