postprocessor for 3dlut colcorr; dithering should be managed in "dirty" way

dirty way: loads dithered/passthru shader according to the game's config (boolean fxdither)

assets/passthru.frag

@@ -0,0 +1,14 @@
+#version 120
+#ifdef GL_ES
+    precision mediump float;
+#endif
+
+
+varying vec4 v_color;
+varying vec2 v_texCoords;
+uniform sampler2D u_texture;
+
+
+void main(void) {
+    gl_FragColor = texture2D(u_texture, v_texCoords);
+}