Default to x64 platform over x86 for the CLI.

src/CLI/Options.cs

@@ -37,7 +37,7 @@ namespace CppSharp
 
         public TargetPlatform? Platform { get; set; }
 
-        public TargetArchitecture Architecture { get; set; } = TargetArchitecture.x86;
+        public TargetArchitecture Architecture { get; set; } = TargetArchitecture.x64;
 
         public GeneratorKind Kind { get; set; } = GeneratorKind.CSharp;