kivy:Improve startup speed

gui/kivy/data/glsl/header.fs

@@ -0,0 +1,10 @@
+#ifdef GL_ES
+    precision highp float;
+#endif
+
+/* Outputs from the vertex shader */
+varying vec4 frag_color;
+varying vec2 tex_coord0;
+
+/* uniform texture samplers */
+uniform sampler2D texture0;