DoF compatibility fix

Platforms without float texture support won't get any front plane DoF, but that's better than nothing I guess

Author: Chman

PostProcessing/Runtime/Effects/DepthOfField.cs

@@ -108,11 +108,11 @@ RenderTexture CheckHistory(int id, int width, int height, RenderTextureFormat fo
 
         public override void Render(PostProcessRenderContext context)
         {
-            var colorFormat = RenderTextureFormat.ARGBHalf;
+            var colorFormat = RenderTextureFormat.DefaultHDR;
             var cocFormat = SelectFormat(RenderTextureFormat.R8, RenderTextureFormat.RHalf);
 
             // Avoid using R8 on OSX with Metal. #896121, https://goo.gl/MgKqu6
-            #if UNITY_EDITOR_OSX || UNITY_STANDALONE_OSX
+            #if (UNITY_EDITOR_OSX || UNITY_STANDALONE_OSX) && !UNITY_2017_1_OR_NEWER
             if (SystemInfo.graphicsDeviceType == UnityEngine.Rendering.GraphicsDeviceType.Metal)
                 cocFormat = SelectFormat(RenderTextureFormat.RHalf, RenderTextureFormat.Default);
             #endif