Fix building with Visual Studio 2013

[Holiverh]

So after fiddling with it 🎱 for a bit I managed to get zordzman-server built and running with VS 2013. However it did require a bit too much manual tweaking which should probably be fixed:

1. The FindSDL2* CMake modules don't deal with the x86/ and x64/ directories in lib/. I ended up copy-pasting them up a level as a lazy fix.
2. The include directories seem to have a SDL2/at the end of them even though the SDL2 distribution for Windows just sticks them in include/.
3. The SDL2_image include path was all kinds of wrong. It was set to NOTFOUND even though CMake did seem to be able to find it because it let me generate the .sln.
4. The version of json11 we use won't build at all in VS2013 because of its use of noexcept and snprintf. There are currently two PRs open on json11 which claim to fix it. I tried Visual Studio 2013 support dropbox/json11#14 which seems to work.
5. The DLLs don't get copied into the build directory.

I haven't attempted to build the client yet.

[crumblingstatue]

While I am not opposed to supporting VS 2013, I will not help with it, as it is an inferior master race C++11 implementation.

Good luck on your quest!

PS.: 🎱

[Rodrun]

Is THIS still active?? I don't think anybody has done anything about this issue.

[pastagatsan]

We should probably keep it open. We still might try to do something about it.

[pastagatsan]

We're on our way there, I have merged @Holiverh's fork so the client uses python for networking.