added support for RGBE header HDR files

stb_image.h

@@ -6147,10 +6147,11 @@ static float *stbi__hdr_load(stbi__context *s, int *x, int *y, int *comp, int re
    int len;
    unsigned char count, value;
    int i, j, k, c1,c2, z;
-
+   const char *headerToken;
 
    // Check identifier
-   if (strcmp(stbi__hdr_gettoken(s,buffer), "#?RADIANCE") != 0)
+   headerToken = stbi__hdr_gettoken(s,buffer);
+   if (strcmp(headerToken, "#?RADIANCE") != 0 && strcmp(headerToken, "#?RGBE") != 0)
       return stbi__errpf("not HDR", "Corrupt HDR image");
 
    // Parse header