Some weekend stable kernel updates

The
4.18.18,
4.14.80,
4.9.136,
4.4.163, and
3.18.125
stable kernel updates have all been released; each contains a relatively
large set of important fixes.

The 3.18.x updates may be about to come to an end, since it is not clear
that anybody is using them. 'And from what I can
see in the 'real world', no one is actually updating devices that rely
on 3.18.y to the newer kernel releases. So I think I'm going to stop
maintaining this tree soon unless someone speaks up and says 'I am using
it!''