Add new CONTRIBUTING.md

[david-a-wheeler]

There's no CONTRIBUTING.md file to provide information to
contributors. Here's a starter one. I'm sure it can be improved,
but that's easier once there's one to improve :-).

Signed-off-by: David A. Wheeler dwheeler@dwheeler.com

[curiousdannii]

I'm not sure we really want to be encouraging other licenses, things are much simpler if everything here is CC BY.

[david-a-wheeler]

I didn't say "instead of CC-BY", I said "including CC-BY". CC-BY is still listed as an option, so anyone could use the example under the terms of CC-BY-4.0. I think it's wise to document how to provide other license options, because some people (including me) will want to provide other options.

This is an attempt to resolve a broader problem: As a "default choice" for software, CC-BY is not really a great choice. The Creative Commons specifically recommends not using CC-BY and other CC licenses for software, since they weren't intended for software. For example, in CC-BY-4.0 there's no concept of source vs. compiled versions, because the license wasn't intended for software. CC-BY-4.0 is also different from the Inform7 license, which uses Artistic-2.0, so anything under only the CC-BY-4.0 license can't be easily moved into the Inform7 distribution.

I realize that this license choice has already been made by many, and I respect that. It's not a disaster. However, I think it'd be wise to allow other licenses in addition to CC-BY. For example, some may want their extension to be moveable into Inform7 itself. To do that, they will eventually have to license or relicense it under Artistic-2.0. Doing that from the beginning eliminates relicensing problems later. You can still document that the entire suite is CC-BY-4.0 if every extension includes CC-BY-4.0 as an option. I'm not sure that a single LICENSE statement makes sense because this is really a "distribution" of extensions, but I understand the desire for simplicity.