Remove some superfluous calls to check_gl_errors

src/atmos_layer.rs

 
         let scale_uniform = program.get_uniform_id(cx, CStr::from_bytes_with_nul(b"scale\0").unwrap()).unwrap();
 
-        check_gl_errors!(cx);
-
         AtmosLayer {
             buffer,
             program,

src/marker_layer.rs

             include_bytes!("../shader/marker.vert"),
             include_bytes!("../shader/marker.frag"),
         ).unwrap();
-        check_gl_errors!(cx);
 
         //TODO Create textures for higher DPI factors / use mipmaps
         let texture = {

src/mercator_tile_layer.rs

     ) -> MercatorTileLayer
     {
         let buffer = Buffer::new(cx, &[], 0);
-        check_gl_errors!(cx);
         cx.bind_buffer(buffer.id());
+        check_gl_errors!(cx);
 
         let mut program = Program::new(
             cx,
             &VertexAttribParams::new(4, 8, 4)
         );
 
-        check_gl_errors!(cx);
-
         MercatorTileLayer {
             program,
             buffer,

src/ortho_tile_layer.rs

             &VertexAttribParams::new(4, 9, 5)
         );
 
-        check_gl_errors!(cx);
-
         OrthoTileLayer {
             program,
             buffer,