Allow 64-bit executables

From the README file: https://gitlab.com/ddobrev/QtSharp/blob/master/README.md

You can use QtSharp with any C# IDE, including Visual Studio, but make sure your executable is 32-bit by either using the x86 configuration or AnyCPU with "Prefer 32-bit" checked.

Having to use a 32-bit executable is kinda a deal breaker for me. Please allow using 64-bit executables.