Fix a collection of minor style violations.

This enables several new StyleCopAnalyzer rules to
be enabled immediately during migration.

OpenRA.Mods.Common/Widgets/VqaPlayerWidget.cs

@@ -87,7 +87,7 @@ namespace OpenRA.Mods.Common.Widgets
 
 			var scaledHeight = (int)videoSize.Y;
 			overlay = new uint[Exts.NextPowerOf2(scaledHeight), 1];
-			var black = (uint)255 << 24;
+			var black = 255U << 24;
 			for (var y = 0; y < scaledHeight; y += 2)
 				overlay[y, 0] = black;