Add support for windows development using Visual studio

[varsnotwars]

This could help with contributions. Visual Studio is also great for c++ dev.

[jagerman]

Visual Studio is also great for c++ dev.

Consider me triggered.

But first, let me say this: we are willing to consider patches to make it work in MSVC—and if it gets working we'll try not to deliberately break it—but it's not something that we are going to voluntarily undertake anytime soon.

The reason why is that MSVC is only great for C++ dev work if MSVC is your primary development environment. Windows devs don't seem to understand this point very well, in my experience: Microsoft's goals with MSVC are not to make a good C++ compiler, it is to suck people into MSVC and Windows and keep them there. This is in stark contrast to actual open source compilers that have neither desire nor incentive to lock you into their platforms.

In particular, MSVC presents all of these problems to an open source project like Lokinet:

• It has a (deserved) reputation for piss poor standard compliance. It didn't even properly support C++11 until the later iterations of MSVC 2017, while every other major compiler supported nearly all of it before 2011.
• Even the standard things it does support it doesn't always properly support (and often just crashes on perfectly valid C++).
• It tends to require a fair number of workarounds and hacks in the code to turn your C++ standard-compliant code into C++ standard-compliant code that MSVC is happy with that doesn't spew endless false positive warnings about everything under the sun.
• Microsoft is horrible about taking, responding to, or being open about bug reports in MSVC.
• It is closed source but even worse, completely unavailable on open source platforms.
• Windows tooling is not amenable to automation (unless you are a big corporate player who is willing to buy expensive software licensing and support contracts from Microsoft). This is the single biggest thing that prevents MSVC from being a first-tier support target for us: all of our platform builds are fully automatic (the only manual step is signing of binaries when we make a release).

Now, that said, I have heard that MSVC 2019, especially the later point updates, has improved the standards compliant situation considerably, and so it might well be less painful than it would have been 3 or 4 years ago. The years of buggy, dumpster fire releases that Microsoft forced onto people, however, deservedly give it a bad reputation that will last a long, long time for people who have had to deal with it in the past.