Implement SDL handler

[Megamouse]

Known issues:

• Config only cares for pad name, which might not be unique won't implement for now
• Add proper description
• Fix rumble nonsense
• Fix xbox controller nonsense
• Rumble doesn't work properly
• Crashes sometimes when SDL is initialized or closed
• Fix HAVE_SDL2

[oresttokovenko]

Can someone merge this?

[AniLeo]

Of course it's not going to be merged before it's completed. The author has merge permissions so they can do it themselves when it's ready.

[oresttokovenko]

Of course it's not going to be merged before it's completed. The author has merge permissions so they can do it themselves when it's ready.

Sorry! I thought it was completed.

[Megamouse]

Merging without linux support for now since there seem to be linker issues with system SDL