Remove contrib/examples/*

Remove contrib/examples/*

There were some side discussions at Git Merge this year about how we
should just update the README to tell users they can dig these up from
the history if the need them, do that.

Looking at the "git log" for this directory we get quite a bit more
patch churn than we should here, mainly from things fixing various
tree-wide issues.

There's also confusion on the list occasionally about how these should
be treated, "Re: [PATCH 1/4] stash: convert apply to
builtin" (<CA+CzEk9QpmHK_TSBwQfEedNqrcVSBp3xY7bdv1YA_KxePiFeXw@mail.gmail.com>)
being the latest example of that.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>