[starling] Fixed tint black shader. See #1003

spine-starling/spine-starling/src/spine/starling/TwoColorEffect.as

@@ -54,10 +54,11 @@ package spine.starling {
 			var fragmentShader : String = [
 			tex("ft0", "v0", 0, texture),   	// ft0 = texture2d(texCoords)
 			"mul ft1, ft0, v1",					// ft1 = texColor * light
+			"sub ft3.xyz, ft0.www, fc0.xyz",    // ft3 = texColor.a - 1
 			"sub ft2.xyz, fc0.xyz, ft0.xyz",	// ft2.xyz = (1 - texColor.rgb)
-			"mul ft2.xyz, ft2.xyz, v2.xyz",		// ft2.xyz = (1 - texColor.rgb) * dark.rgb
-			"mul ft2.xyz, ft2.xyz, ft1.www",	// ft2.xyz = (1 - texColor.rgb) * dark.rgb * alpha
-			"add ft2.xyz, ft2.xyz, ft1.xyz",	// ft2.xyz = (1 - texColor.rgb) * dark.rgb * alpha + texColor.rgb * light.rgb
+			"add ft2.xyz, ft2.xyz, ft3.xyz",    // ft2.xyz = ((texColor.a - 1.0) + 1.0 - texColor.rgb)
+			"mul ft2.xyz, ft2.xyz, v2.xyz",		// ft2.xyz = ((texColor.a - 1.0) + 1.0 - texColor.rgb) * dark.rgb			
+			"add ft2.xyz, ft2.xyz, ft1.xyz",	// ft2.xyz = ((texColor.a - 1.0) + 1.0 - texColor.rgb) * dark.rgb + texColor.rgb * light.rgb
 			"mov ft2.w, ft1.w",					// ft2.w = alpha
 			"mov oc, ft2"
 			].join("\n");