EPL1.0 -> EPL2.0 and contribute.md

[svenefftinge]

This PR changes the code license from EPL 1.0 to EPL 2.0 and adds a Contribute.md file.

see https://github.com/eclipse/xtext/issues/1176

[cdietrich]

@svenefftinge looks like you missed half of the header changes

https://www.eclipse.org/projects/handbook/#ip-copyright-headers

see also https://bugs.eclipse.org/bugs/show_bug.cgi?id=530393

[cdietrich]

Things to look at

• complete headers
• LICENSE / license.html / epl*html
• about.html / about.properties
• ..... to be checked
• maven metadata / poms (also in gradle)
• feature.xml / feature.properties / license feature in target

https://www.eclipse.org/legal/guidetolegaldoc2.php https://www.eclipse.org/projects/handbook/#ip-copyright-headers

[waynebeaton]

I really hate to do this, but... while you updated the URLs correctly, you missed the text in at least some of the headers...

[cdietrich]

@svenefftinge nice. looks much better now. still miss an update to the license feature in the target file

[svenefftinge]

Yes, I was still on it. But now I hope I have it. Can you review, please? I'll go through the other PRs once this is good to merge.

[cdietrich]

the target file is still not there. or github does not show it https://github.com/eclipse/xtext-lib/blob/8888f2dc2195ad65565779296bc6ba27031cb1e7/releng/releng-target/xtext-lib.target.target#L10

[svenefftinge]

Thanks, I have updated the target file and replaced the whole contents of the about files.

[cdietrich]

ok will recheck later @szarnekow @miklossy can you please also have a look