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/gl330/blur.fs

@@ -0,0 +1,29 @@
+#version 330
+
+in vec2 fragTexCoord;
+
+out vec4 fragColor;
+
+uniform sampler2D texture0;
+uniform vec4 tintColor;
+
+// NOTE: Add here your custom variables
+
+const float renderWidth = 1280;
+const float renderHeight = 720;
+
+float offset[3] = float[](0.0, 1.3846153846, 3.2307692308);
+float weight[3] = float[](0.2270270270, 0.3162162162, 0.0702702703);
+
+void main()
+{
+    vec3 tc = texture2D(texture0, fragTexCoord).rgb*weight[0];
+
+    for (int i = 1; i < 3; i++) 
+    {
+        tc += texture2D(texture0, fragTexCoord + vec2(offset[i])/renderWidth, 0.0).rgb*weight[i];
+        tc += texture2D(texture0, fragTexCoord - vec2(offset[i])/renderWidth, 0.0).rgb*weight[i];
+    }
+
+    fragColor = vec4(tc, 1.0);
+}