Change readme, license, descriptions

[Wuzzy2]

THIS IS ONLY A PREVIEW PR! DO NOT MERGE BEFORE #13!

This PR changes the OpenSFX license, the README and the public descriptions. (This is phase 4 of the roadmap (#9).)

The OpenSFX license is now described as follows:

• CC BY-SA 3.0 for the sounds
• GPLv2+ and CDDL 1.1 for everything else (this is dual-licensing, the user is granted both licenses, meaning they can pick which one applies to them)

Justification: In general, my goal is to make OpenSFX 100% libre. Therefore, only libre licenses can be allowed. It always bothered me that the "Open" in "OpenSFX" is so wrong. ;-)

All sounds are now (AFTER #13 IS MERGED) under CC0, CC BY 3.0 or CC BY-SA 3.0. The only possible choice for the overall sound license is thus CC BY-SA 3.0. Evidence for this has been fully documented in the readme and src/opensfx.sfo.

GPLv2+ and CDDL 1.1 was chosen because the text and scripting files originate from Rubidium, who has later gave permission to relicense their work under those licenses. So the only choice was to use one of those, or both. I chose both, also called “dual-licensing” (rather than just picking one of the two licenses) because for pragmatic reasons, it gives the user more choice, possibly reducing legal pain later on. Evidence of permission: https://dev.openttdcoop.org/issues/1364

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Please, please, PLEASE do a careful review of this PR, because it's quite significant. This PR represents a MAJOR milestone in OpenSFX' history, and it needs to be get absolutely right. Please check for any mistakes or logical errors in this PR.

[planetmaker]

The build "system" is mainly my work as also the history of this repository indicates; Rubidiums intial version did not have any. So an open-source license choice (preferrably GPL v2+) should not be limited by any reference to the build files; any CC license with the the exception of -NC and -ND parts is ok for me, too.

[Wuzzy2]

So are you OK with my suggestion of the dual-license, i.e. "GPLv2+ or CDDL 1.1"?

If yes, I see no reason to not apply this licensing to all non-sound files. Remember, Rubidium retroactively gave permission to ALL their files, so it's fine.

If it would be possible, I would also be OK if the entire repo is under CC BY-SA 3.0. I don't really care that much, I just want to make sure that everything is unambigiously under FOSS licensing.

[planetmaker]

Yes, totally fine with me to dual-license it that way.

[LordAro]

Presumably needs a rebase to remove the "changing sounds" commit

[Wuzzy2]

Thanks for your comments, I will work on this in a couple of hours.

Btw: It is indeed "macOS" (See Wikipedia).

[Wuzzy2]

OK, I did all the required updates. I have re-done the commits to be compatible with master again, but it required a force-push.

I have added one other change tho: I noticed that descriptions.ptxt is actually not neccessary anymore. This file contains the same strings as in lang and is redundant. Also, when running make, only the files in lang are relevant, the descriptions.ptxt is ignored. Likewise, lang/translations.sh was deleted as well as its only purpose is to generate a descriptions.ptxt.

[Wuzzy2]

I have just fixed a very dumb mistake! I accidentally have had the GPLv2 text twice in license.txt. The second GPLv2 text was in the section for CDDL. Ouch ...

Anyway, I have looked all on my changes again, checking one last time for possible mistakes, and it looks good for me now. This PR is now officially ready for a review and no longer a "preview PR".

[Wuzzy2]

I have just removed the outdated language files since the translations in those files are no longer correct, due to the license change.

[LordAro]

I no longer have any issues with this. I will defer to @orudge for another approval & merge however