Merge branch 'component-ids' of https://github.com/jeremysawicki/stb into working

stb_image.h

@@ -2929,13 +2929,8 @@ static int stbi__process_frame_header(stbi__jpeg *z, int scan)
    for (i=0; i < s->img_n; ++i) {
       static unsigned char rgb[3] = { 'R', 'G', 'B' };
       z->img_comp[i].id = stbi__get8(s);
-      if (z->img_comp[i].id != i+1)   // JFIF requires
-         if (z->img_comp[i].id != i) {  // some version of jpegtran outputs non-JFIF-compliant files!
-            // somethings output this (see http://fileformats.archiveteam.org/wiki/JPEG#Color_format)
-            if (z->img_comp[i].id != rgb[i])
-               return stbi__err("bad component ID","Corrupt JPEG");
-            ++z->rgb;
-         }
+      if (z->img_comp[i].id == rgb[i])
+         ++z->rgb;
       q = stbi__get8(s);
       z->img_comp[i].h = (q >> 4);  if (!z->img_comp[i].h || z->img_comp[i].h > 4) return stbi__err("bad H","Corrupt JPEG");
       z->img_comp[i].v = q & 15;    if (!z->img_comp[i].v || z->img_comp[i].v > 4) return stbi__err("bad V","Corrupt JPEG");