Low latency kernels

[Ben Collins]

I've added a -lowlatency kernel for feisty (x86 and x86_64 targets
only). They'll show up in the next kernel upload. Right now it's the
same as the -generic kernel, but with 1000HZ and PREEMPT.

I'll take some direction from UbuntuStudio to define more fine tuning if
needed.

These kernels will be in universe, because I don't want to support them
officially. Anyone filing a kernel bug running these kernels will be
asked to reproduce it on a -generic kernel. Any real bugs with these
kernels will be given "low" priority at best.

I'll have linux-restricted-modules compiled against them as well and
linux-meta packages, so you can simply install linux-image-lowlatency to
get an easy switch.