Refactor for blender 2.8 and new shader model

Shaders/CModelShaders.common.glsl

@@ -0,0 +1,18 @@
+#extension GL_ARB_enhanced_layouts: enable
+#extension GL_ARB_shader_image_load_store: enable
+
+struct VertToFrag {
+  vec4 mvPos;
+  vec4 mvNorm;
+  vec4 color;
+  vec2 lightmapUv;
+  vec2 diffuseUv;
+  vec2 emissiveUv;
+  vec2 specularUv;
+  vec2 extendedSpecularUv;
+  vec2 reflectionUv;
+  vec2 alphaUv;
+  vec2 extUvs[3];
+  vec2 dynReflectionUvs[2];
+  float dynReflectionAlpha;
+};