Added shaders and textures for the main menu.

assets/shaders/bckg/bckg.frag

@@ -0,0 +1,12 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform sampler2D u_texture;
+uniform vec2 u_scaling;
+
+varying vec2 v_texCoords;
+
+void main(){
+	gl_FragColor = texture2D(u_texture, v_texCoords * u_scaling);
+}