Improve Copyright Notices

[H0R5E]

Originally posted by @kmruehl in #65

There are a few jobs to do for the copyright notices. These are:

• [x] Get NTESS approval
• [x] Add copyright statement to README
• [x] Replace verbatim license in docs with source code boilerplate
• [x] Update copyright header throughout (if necessary)
• [x] Rename LICENSE as COPYING
• [x] Convert axiMesh license to GPL
• [x] Check license of code in Penalba, Markel, Thomas Kelly, and John V. Ringwood (2017)

[ryancoe]

Here's the paper where I've adapted some of the Nemoh interfacing from:

Penalba, Markel, Thomas Kelly, and John Ringwood. "Using NEMOH for modelling wave energy converters: A comparative study with WAMIT." (2017).

The source is available here: http://www.eeng.nuim.ie/coer/downloads. Looks like an Apache 2.0 license.

[ryancoe]

Copyright 2020 National Technology & Engineering Solutions of Sandia, LLC (NTESS). Under the terms of Contract DE-NA0003525 with NTESS, the U.S. Government retains certain rights in this software.

[ryancoe]

@H0R5E - I'm going to be tied up tomorrow morning until about 6 PM GMT, I will wrap up anything that you instruct me to at that point.

[H0R5E]

@ryancoe pretty much everything is ready to go, but I'm worried that we can't convert the Apache 2.0 licensed code in getNemoh.m to GPL under the NTESS guidelines. I mean, this is a pretty normal thing to do.

I've also done this in+WecOptLib+utils\isClose.m, which is derived from numpy. That license is MIT, which again can be converted to GPL.