RFR: 8237503: Update copyright header for files modified in 2020

Mon Feb 3 13:17:29 UTC 2020

On Fri, 31 Jan 2020 23:32:55 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

> Fix for [JDK-8237503](https://bugs.openjdk.java.net/browse/JDK-8237503) to update the "last modified" year in the copyright header for all files modified in 2020 in the `jfx14` branch.
> 
> NOTE: I'll update this to pick up any last-minute changes integrated to `jfx14` and then remove the WIP.

@arapte you can take an initial look whenever you are ready. I expect only a few new files to come in, which I will push as an additional commit.

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PR: https://git.openjdk.java.net/jfx/pull/103