support for Erlang R19

[eryx67]

It seems that Erlang 19 has only one (typed) declaration for records in AST

[stevendanna]

@eryx67 Thanks for the contribution!

Our DCO policy (read about it here: https://blog.chef.io/2016/09/19/introducing-developer-certificate-of-origin/) requires that your commit has a Signed-Off-By line affirming you agree to the DCO. You can add it to your existing commit by doing something like:

git commit --amend -s --no-edit

and then force-pushing to your branch.

cc @chef/erlangers for review

[markan]

I was just looking at what it would take to update us to OTP 21 and saw this PR.
@eryx67 thank you for your work and I'd like to revive this PR if possible. Very sorry about it falling through the cracks.

Currently github is marking this as unmergable because not every commit has DCO and travis is failing. While some of the commits have DCO, not all do.

What I would suggest we do is break this PR up into a couple of pieces, each rebased on master, and updated to have DCO. I'm thinking something like this would work:

• The update to R19
• The connection arg improvements.
• Update to OTP 21
• Other functionality

Thoughts? I see you are maintaining a fork, and I think if we do the commits in the above order the git histories will be reconcilable by merge cleanly.