Folders rename for consistency on shaders version

shaders/glsl100/grayscale.fs

@@ -0,0 +1,20 @@
+#version 100
+
+precision mediump float;
+
+varying vec2 fragTexCoord;
+
+uniform sampler2D texture0;
+uniform vec4 fragTintColor;
+
+// NOTE: Add here your custom variables
+
+void main()
+{
+    vec4 base = texture2D(texture0, fragTexCoord)*fragTintColor;
+    
+    // Convert to grayscale using NTSC conversion weights
+    float gray = dot(base.rgb, vec3(0.299, 0.587, 0.114));
+    
+    gl_FragColor = vec4(gray, gray, gray, fragTintColor.a);
+}