Updated the SDL documentation

[lenardg]

Updated the SDL version number in the docs for Visual Studio.
Also, added a bulleted list - on a quick read it was not immediately obvious there are two libraries to get.

[Daft-Freak]

I think we should be consistent about the SDL versions we're recommending/automagically installing... WSL/MinGW docs also specify 2.0.10 and the various CI scripts install that.

Auto-install in vs/sdl/sdl2-config.cmake is doing 2.0.12 though... err...

[lenardg]

I can update the other references as well and add them to this PR.

[lenardg]

Changed every place to be the same version 2.0.14, docs, scripts, everything :)

[Gadgetoid]

Thanks for giving the docs a shakeup and trying to get the SDL setup consistent. It's appreciated!

Judging by the test failures on MinGW I think you also need to update - https://github.com/pimoroni/32blit-beta/blob/master/ci/install_sdl_mingw.sh

[lenardg]

I actually did update that file, and now I am trying to figure out the error logs, why it failed here on Github? Strange.

[Daft-Freak]

There is something nasty going on with SDL's CMake config in the MinGW build... The library path is very wrong...

Partly caused by this: https://github.com/pimoroni/32blit-beta/blob/master/mingw.toolchain#L4-L5 (library name ends up SDL2). But still wrong without that (libSDL2.dll, should be libSDL2.dll.a)

[Daft-Freak]

Okay at least some of it is bugs in SDL's CMake config... (not setting IMPORTED_IMPLIB for Windows, I should probably go open a bug about that...)

Even fixing that and some stuff on the blit side, it still fails because -lmingw32 is getting linked in the wrong place...

[Gadgetoid]

I think this needs rebased to see if it builds with the latest fixes?

[Daft-Freak]

Looks like SDL has fixed the MinGW problem: libsdl-org/SDL@501fe46...

[Daft-Freak]

Yep, 2.0.16 works: master...Daft-Freak:lenardg/docs/sdl

[Gadgetoid]

Replaced by #783 - thank you all!