Added some useful postprocessing shaders

Shaders come in two flavours:
- shaders/gl330: OpenGL 3.3+ (Windows, Linux, OSX)
- shaders/gles100:  OpenGL ES 2.0 (Android, RPI, HTML5)

shaders/gles100/base.vs

@@ -0,0 +1,21 @@
+#version 100
+
+attribute vec3 vertexPosition;
+attribute vec2 vertexTexCoord;
+attribute vec3 vertexNormal;
+
+varying vec2 fragTexCoord;
+
+uniform mat4 projectionMatrix;
+uniform mat4 modelviewMatrix;
+
+// NOTE: Add here your custom variables 
+
+void main()
+{
+    vec3 normal = vertexNormal;
+    
+    fragTexCoord = vertexTexCoord;
+    
+    gl_Position = projectionMatrix*modelviewMatrix*vec4(vertexPosition, 1.0);
+}