Improve gamma shader parity - fixes #611 (#790)

* Call gamma post process after `ui.render` #611

* Fixed "washed out" look.

* Improve gamma pass and cache viewport size

Minecraft.Client/Durango/Durango_Minecraft.cpp

@@ -27,6 +27,7 @@
 #include "Leaderboards\DurangoLeaderboardManager.h"
 #include "..\..\Minecraft.Client\Tesselator.h"
 #include "..\..\Minecraft.Client\Options.h"
+#include "..\GameRenderer.h"
 #include "Sentient\SentientManager.h"
 #include "..\..\Minecraft.World\IntCache.h"
 #include "..\Textures.h"
@@ -832,6 +833,9 @@ void oldWinMainTick()
 #endif
 		ui.tick();
 		ui.render();
+
+		pMinecraft->gameRenderer->ApplyGammaPostProcess();
+
 #if 0
 		app.HandleButtonPresses();