Stable kernel updates

Greg KH has released stable kernels 4.3.3,4.2.8, and 4.1.15. All of them contain important fixes.This will be the last 4.2.y kernel. Users of the 4.2 kernel should upgradeto the 4.3.y kernel series.

Update: Canonical's kernel team will pick upstable maintenance of 4.2 where Greg left off.