move shaders into .glsl files and add #include feature

data/shaders/color.glsl

@@ -0,0 +1,16 @@
+[[vertex]]
+uniform mat4 mvp;
+in vec4 pos;
+void main()
+{
+   gl_Position = mvp * pos;
+   gl_PointSize = 5.0;
+};
+
+[[fragment]]
+uniform mediump vec4 col;
+out mediump vec4 frag;
+void main()
+{
+   frag = col;
+};