[unity] Fix Tint and TintBlack shaders ignoring alpha.

spine-unity/Assets/spine-unity/Modules/Shaders/Spine-Skeleton-Tint.shader

@@ -52,7 +52,7 @@ Shader "Spine/Skeleton Tint" {
 
 			float4 frag (VertexOutput i) : COLOR {
 				float4 texColor = tex2D(_MainTex, i.uv);
-				return (texColor * i.vertexColor) + float4(((1-texColor.rgb) * texColor.a * _Black.rgb), 0);
+				return (texColor * i.vertexColor) + float4(((1-texColor.rgb) * _Black.rgb * texColor.a*_Color.a*i.vertexColor.a), 0);
 			}
 			ENDCG
 		}

spine-unity/Assets/spine-unity/Modules/SkeletonGraphic/Shaders/Spine-SkeletonGraphic-TintBlack.shader

@@ -110,7 +110,7 @@ Shader "Spine/SkeletonGraphic Tint Black (Premultiply Alpha)"
 				clip (texColor.a - 0.001);
 				#endif
 
-				return (texColor * IN.color) + float4(((1-texColor.rgb) * texColor.a * (_Black.rgb + float3(IN.uv1.r, IN.uv1.g, IN.uv2.r))), 0);
+				return (texColor * IN.color) + float4(((1-texColor.rgb) * (_Black.rgb + float3(IN.uv1.r, IN.uv1.g, IN.uv2.r)) * texColor.a*_Color.a*i.vertexColor.a), 0);
 			}
 		ENDCG
 		}

spine-unity/Assets/spine-unity/Shaders/Spine-Skeleton-TintBlack.shader

@@ -61,7 +61,7 @@ Shader "Spine/Skeleton Tint Black" {
 
 			float4 frag (VertexOutput i) : COLOR {
 				float4 texColor = tex2D(_MainTex, i.uv);
-				return (texColor * i.vertexColor) + float4(((1-texColor.rgb) * texColor.a * (_Black.rgb + float3(i.uv1.r, i.uv1.g, i.uv2.r))), 0);
+				return (texColor * i.vertexColor) + float4(((1-texColor.rgb) * (_Black.rgb + float3(i.uv1.r, i.uv1.g, i.uv2.r)) * texColor.a*_Color.a*i.vertexColor.a), 0);
 			}
 			ENDCG
 		}