RFR: Add missing copyright headers

[Erik Helin]

On Fri, 12 Mar 2021 16:00:35 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> Multiple java files are missing copyright headers. I have now added proper copyright headers for those.
> 
> The starting year in the copyright line was determined by "git log --follow" on each file, and using the year of the first commit. Some commit messages indicated that the code might have arrived there due to some refactoring, but I have not been motivated digging down further to track the origins of the code.

Looks good!

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Marked as reviewed by ehelin (Reviewer).

PR: https://git.openjdk.java.net/skara/pull/1055