Update copyright headers for 2018

[pzel]

Our copyright headers currently say:

Copyright 2017 The Wallaroo Authors.

Let's update it to say:

Copyright 2017-2018 The Wallaroo Authors.

[SeanTAllen]

I don't believe this matters. There's no legal requirement to update as far as I know.

If that is the case, this seems like extra work that we don't need to do that adds noise to history etc.

Is there a reason to do this?

[pzel]

I only brought this up in the name of consistency -- if we're furnishing our source files with dates, it makes sense to keep doing it.

I understand the fact about adding noise to history, fair enough. If you think this is unnecessary to do in one fell swoop, I'm not going to press the issue. I do think we should be updating the copyright headers in files that we touch in the course of regular work.

Or drop the headers, and put a nice big COPYRIGHT file in the project root.

[SeanTAllen]

We can't drop all of them. Some are still BSD and not Wallaroo copyright (derived from Pony code).

[jtfmumm]

@pzel Can we close this?