move shaders into .glsl files and add #include feature

data/shaders/vertex-color.glsl

@@ -0,0 +1,19 @@
+[[vertex]]
+uniform mat4 mvp;
+in vec4 pos;
+in vec4 col;
+out vec4 c;
+void main()
+{
+   c = col;
+   gl_Position = mvp * pos;
+   gl_PointSize = 5.0;
+};
+
+[[fragment]]
+in mediump vec4 c;
+out mediump vec4 frag;
+void main()
+{
+   frag = c;
+};