imgui_impl_sdl and main sample

[CedricGuillemet]

Impl & main sample only

[ocornut]

Thanks! Will look into it (probably after 1.39 release)

[ocornut]

OK i have merged that with a few minor tweaks/fixes.
There's no script/Makefile/project to build it though. That's the really annoying part to get done but in the meanwhile the code is committed for reference.

I am building with

cl /MD main.cpp imgui_impl_sdl.cpp ..\..\imgui.cpp -I..\.. -ID:\T-Work\Libs\SDL\SDL2-2.0.3\include /link /libpath:D:\T-Work\Libs\SDL\SDL2-2.0.3\lib\x86 SDL2.lib SDL2main.lib opengl32.lib /subsystem:console

Will look into adding a Makefile or cmakelist file or creating a MSVC project. I would ideally want the MSVC project to be in the solution with the other examples but I'm not sure how to do that without requiring the user to have a copy of SDL yet.

[ocornut]

Made some reorganisation, the event loop is moved to main.cpp which make sense so that imgui_sdl_impl.cpp is more likely "copiable" into user's application.

4167528