Link to the license is invalid

[ivan-mogilko]

We have a link which is supposed to open Artistic License 2 text in the License.txt, and every code file header. The link is:
http://www.opensource.org/licenses/artistic-license-2.0.php

Recently I tried to open this link and was told that this page cannot be found. I do not know whether it was available earlier, and when did it become invalid.

Searching the opensource.org for Artistic License 2 points to this page instead:
https://opensource.org/license/artistic-2-0/

I guess we should replace the link everywhere through the repository, in the maintained branches (starting with release-3.6.0), in the manual, and on the website, if it also is present there.
(Also see #2131)

[ivan-mogilko]

Since there's a need to adjust all the source file headers, in them we have the copyright years written as:
// Copyright (C) 1999-2011 Chris Jones and 2011-20xx others

I always wondered if this is permitted to do something like this. Others (major projects at least) seem to just update each year, for example:
libsdl-org/SDL@fde78d1

[ivan-mogilko]

I think the best way would be to write another python script in Scripts/ dir and add one that runs through the whole repo and applies this to all files that need and contain this form. Values may be read from version.json as well.

[ivan-mogilko]

Fixed by #2212 in multiple branches.