Better gradient handling (migration/fallbacks)

[Clemens Eisserer]

> We just need to accelerate gradients, and is where any effort in
> software should occur.  It's on our schedule, but not for quite a while.
> Setting up the X Server to allow drivers to request gradients was easy
> last time I did it, though I've misplaced the branch it looks like.
> Then someone would just have to write the shader for it, and for
> 915-class hardware that shouldn't be hard.
Glad to know its on your schedule.
Of course accalerated gradients would be even better :)

Thanks for your reply, Clemens