Merge branch '236-zmq-build-new-module' into 'master'

Resolve "zmq: build new module"

Closes #236

See merge request Pmodules/buildblocks!337

Libraries/zeromq/build

+#!/usr/bin/env modbuild
+
+pbuild::set_download_url "https://github.com/zeromq/libzmq/releases/download/v${V_PKG}/$P-${V_PKG}.tar.gz"
+pbuild::add_to_group 'Libraries'
+#pbuild::install_docfiles 'COPYING' 'README.md'
+
+# Local Variables:
+# mode: sh
+# sh-basic-offset: 8
+# tab-width: 8
+# End:

Libraries/zeromq/files/variants.yaml

+overlay: base
+group: Libraries
+zeromq/4.3.4:
+  - relstage: stable

Libraries/zeromq/modulefile

+#%Module1.0
+
+module-whatis		"open-source universal messaging library"
+module-url		"https://zeromq.org"
+module-license		"GNU GPL/LGPL v3"
+module-maintainer	"Achim Gsell <achim.gsell@psi.ch>"
+
+module-help	"
+ZeroMQ looks like an embeddable networking library but acts like a
+concurrency framework. It gives you sockets that carry atomic messages
+across various transports like in-process, inter-process, TCP, and
+multicast. You can connect sockets N-to-N with patterns like fan-out,
+pub-sub, task distribution, and request-reply. It's fast enough to be
+the fabric for clustered products. Its asynchronous I/O model gives you
+scalable multicore applications, built as asynchronous message-processing
+tasks. It has a score of language APIs and runs on most operating systems.
+"