Heads up: Contributions and advertisement clause

[Joerg Sonnenberger]

Hi all,
in the recent discussion, there was a consent that the fourth clause of
the original BSD license is mostly unnecessary now. It is still in a lot
of our code base, waiting to be cleaned up. For this to easier in the
future, I'd like to ask all commiters and distributers to answer this
mail if they agree with the removal. For those parts an explicit
adversitement is wanted, it should be noted explicitly.

Doing it now saves us the paperwork for tracing down our own changes later.
We only have to verify / merge with FreeBSD, which is time consuming enough.

Joerg