Merge pull request #811 from hintjens/master

Cleanups to containers
Problem: CI tests many builds with one matrix item
Solution: Split CI builds into separate matrix items
This is done with an entry in 'env' for each build
Merge pull request #812 from hintjens/master

Problem: extended containers are non-trivial to learn
Merge pull request #813 from jemc/master

Problem: CI tests many builds with one matrix itemThis
Merge pull request #815 from hintjens/master

Problem: zsock and zgossip_msg don't build on ZMQv2
Added the tcp bind syntax [-60000] to the examples.
Fixed spacing to match surrounding lines.
Merge pull request #816 from WyoMurf/master

Doc fixes-- added example to bind syntax
Bring docs up to date wrt the deprecated zframe_recv_nowait.
Merge pull request #817 from WyoMurf/master

Bring docs up to date wrt the deprecated zframe_recv_nowait.
Resolve integer narrowing and sign mismatch warnings.
Remove extraneous symbol.
Fix forcing to/from bool warnings.
Merge pull request #820 from evoskuil/master

Remove extraneous symbol causing VC/mingw break, fix warnings.
Add missing exports to zgossip functions.
Workaround for unresolved external error in VS test builds.
Merge pull request #821 from evoskuil/master

Fix and workaround unresolved externals in VS builds.
Problem: string buffers aren't NULL checked
fix mingw autoconf build

presence of "-no-undefined" seems to require dependent libraries to be
linked in.

as this file is autogenerated, someone needs to fix
"model/build-autoconf.gsl"
remove unused variable

when compiling with mingw, -Werror causes compilation to fail