Mono-compiled HWSEdit and Mac .app packaging

This adds a build of HWSEdit.exe compiled with Mono. Also, the Mono build is packaged into a Mac .app, which requires the Mono runtime of version 3.10.0.26 or newer installed.

I'm still not sure this is the best way to do things. I didn't think you had to had to recompile things for Mono, but I can't run your existing builds. Do my Mono builds run on Windows too? Is there a way to properly build things on Windows that run on mono too?

This is what happens if I try to run the existing builds you had:

    $ mono hws2xml.exe
    Stack overflow in unmanaged: IP: 0x95e0c92b, fault addr: 0xbf75ce4c

This commit also adds HWSEdit.exe packaged into a Mac .app. The user still needs a very recent (currently unreleased) build of the Mono runtime installed. But the .app can easily double clicked and run.

And the dist/ directory of binaries is totally against proper version control practices. You may want to consider [GitHub releases](https://github.com/joedf/HWSEdit/releases) instead for binaries.