Merge pull request #3271 from gabm/Relicense

Problem: gabm didn't signalise his consent to relicense libzmq

RELICENSE/gabm.md

+# Permission to Relicense under MPLv2
+
+This is a statement by Matthias Gabriel 
+that grants permission to relicense its copyrights in the libzmq C++
+library (ZeroMQ) under the Mozilla Public License v2 (MPLv2).
+
+A portion of the commits made by the Github handle "gabm", with
+commit author "Matthias Gabriel <matthias.gabriel@etit.tu-chemnitz.de>", are copyright of Matthias Gabriel.
+This document hereby grants the libzmq project team to relicense libzmq, 
+including all past, present and future contributions of the author listed above.
+
+Matthias Gabriel
+2018/10/8