Add build/net folder to redist package to allow copying native binaries to output folder

[sluki]

build/net would contain package.props with nodes like this:

PreserveNewest

that way when I am reference C++/CLI project that uses these libraries, I can add redist package to my C# project and it will work.

And add options to script file to enable this and to set whether or not should Debug C# projects use Release native libraries etc.