[U-Boot] [ANN] U-Boot v2015.10-rc4 released

Hey all,

I've pushed v2015.10-rc4 out to the repository and tarballs should exist soon.

We're coming up on the release date and I think things are in reasonable shape overall. Please speak up if there's some fixes I'm still overlooking, I thought I grabbed them all by now but I may have still missed something.