[SDL] Force feedback in SDL

[Ryan C. Gordon]

> This is a question that keeps coming up, every once in a while.  And 
> yeah, I'd like to see it too.  But apparently the technology behind 
> force feedback is complicated enough that the developers are having some 
> trouble figuring out a good way to implement it.  The general consensus 
> seems to be, "We'll put this in once we figure out how to do it right."  

It's actually one of the ideas for the Google Summer of Code efforts.

The gist is we need someone to figure out what's available on major 
operating systems, and build a reasonable API that all of them can 
use...which is more or less how all the other parts of SDL work.

The first step is going to be research!
The next step is probably deciding if this runs independently of the 
joystick API, or becomes part of it.

--ryan.