GCodeViewer -> New shaders for options

resources/shaders/options_110.vs

@@ -0,0 +1,11 @@
+#version 110
+
+uniform float zoom;
+// x = min, y = max
+uniform vec2 point_sizes;
+
+void main()
+{
+    gl_PointSize = clamp(zoom, point_sizes.x, point_sizes.y);
+    gl_Position = ftransform();    
+}