Add ability to set custom OCIO function names

app/shaders/chromakey.frag

@@ -39,7 +39,7 @@ void main() {
   vec4 col = texture(tex_in, ove_texcoord);
 
   // Perform color conversion
-  vec4 cie_xyz = %2(col);
+  vec4 cie_xyz = SceneLinearToCIEXYZ_d65(col);
   vec4 lab = CIExyz_to_Lab(cie_xyz);
 
   frag_color = vec4(lab.r);

app/shaders/colormanage.frag

@@ -44,7 +44,7 @@ void main() {
   }
 
   // Perform color conversion
-  col = %2(col);
+  col = OCIODisplay(col);
 
   // Associate or re-associate here
   if (ove_maintex_alpha == ALPHA_ASSOC) {