epmd: support IPv6 node registration

Allow IPv6 nodes to register with and query epmd. On systems with
IPv6 support:

* epmd listens on the IPv4 and IPv6 ANY or loopback sockets

* the epmd cli client connects to epmd using the IPv6 loopback

* distributed nodes started with "-proto_dist inet6_tcp" will register
  with epmd over IPv6
Merge branch 'dg/win_icon' into master-pu
Merge branch 'sk/odbc64' into master-pu
Merge branch 'sal/ftp' into master-pu
Merge branch 'rc/break-out-asserts' into master-pu
Merge branch 'mh/fix-emacs-pkg-flymake-dep' into master-pu
Merge branch 'an/http11_content_length_zero' into master-pu
Merge branch 'sa/dialyzer-types-arity' into master-pu
Merge branch 'mh/cdv-osx-default-browser' into master-pu
Merge branch 'mah/fix-ssh-connect-doc' into master-pu

Conflicts:
	lib/ssh/doc/src/ssh.xml
Merge branch 'as/tls-psk-srp-suites' into master-pu
Merge branch 'ats/observer_tv_improper_lists' into master-pu
Merge branch 'ms/epmd-IPv6-node-reg' into master-pu