Basic GUI

Finally, the GUI version is here. The old version was removed to write a new one, using the .NET 5. This release includes both Console and this raw GUI version which is far from perfect, but already contains some basic functionality (well, actually the whole Console version functionality). What is yet to be done is to optimization, I wasn't doing anything on it. Also, there are a few more new features to bring on here - GUI version already has UI elements for them, just not working.