remove spine integration

samples/bin/library/shaders/spine_shader.frag

@@ -1,10 +0,0 @@
-uniform sampler2D u_texture;
-
-varying vec2 v_st0;
-varying vec4 v_color0;
-
-void main() {
-    vec4 c = texture2D(u_texture, v_st0) * v_color0;
-    c.rgb *= c.a;
-    gl_FragColor = c;
-}

samples/bin/library/shaders/spine_shader.json

@@ -1,4 +0,0 @@
-{
-    "vertex" : "spine_shader.vert",
-    "fragment" : "spine_shader.frag"
-}

samples/bin/library/shaders/spine_shader.vert

@@ -1,36 +0,0 @@
-uniform vec2 u_screen_s;
-uniform mat4 u_matrix_vp;
-
-attribute vec3 a_vertex;
-attribute vec2 a_st0;
-attribute vec4 a_color0;
-
-varying vec2 v_st0;
-varying vec4 v_color0;
-
-vec2 round(vec2 v) {
-    return vec2(
-        floor(v.x + 0.5),
-        floor(v.y + 0.5));
-}
-
-vec4 pixel_snap(vec4 pos) {
-    vec2 hpc = u_screen_s * 0.5;
-    vec2 pixel_pos = round((pos.xy / pos.w) * hpc);
-    pos.xy = pixel_pos / hpc * pos.w;
-    return pos;
-}
-
-vec4 vertex_to_homo(vec3 pos) {
-    return vec4(pos, 1.0) * u_matrix_vp;
-}
-
-void main() {
-    v_st0 = a_st0;
-    v_color0 = a_color0;
-#ifndef VERTEX_SNAPPING_ON
-    gl_Position = vertex_to_homo(a_vertex);
-#else
-    gl_Position = pixel_snap(vertex_to_homo(a_vertex));
-#endif
-}