[Yhc] YHC.NET

Hello Guys, The first version of the .NET backend for YHC is working. It isn't stable yet but at least I managed to run some simple applications with it, using the compiled yhc-base package. The required compiler changes are quite small. I just had to add an additional compiler option which switches from the bytecode backend to the new backend. Everything else is clearly separated from the rest of the compiler. The .NET backend is using its own runtime library and requires some changes in the base package. I tend to release the backend as open source. Would you like to merge the new backend in the main compiler repository? Alternativelly I will have to keep my own copy repository. Cheers, Krasimir