update copyright info in code

[eclare108213]

change 2019 to 2020 in copyright text, elsewhere
add copyright statement to Icepack interface modules

[apcraig]

This has been addressed in #301. It is also addressed in CICE #409.

I cannot find a copyright page on the About-Us / Resource Page. Is there something there?

[eclare108213]

There might not be anything in the About-Us repo. I was thinking of the License files, which are in both the CICE and Icepack repos. Those are pdfs so I'll probably need to update them (and it looks like I didn't do that last year).

[apcraig]

I just had a quick look at the License files, they are pdfs and contain the copyright. Could we convert these to simple text files so they are easier to edit and maintain in the future? If @eclare108213 agrees, I'm happy to do that.

[eclare108213]

Sure. I'd like to see what they look like in final form before we commit to this change. I probably made them pdf originally for the formatting.

[duvivier]

Or pdfs because we didn't want it to be easy for users to change.

[eclare108213]

I just changed the Icepack License file using Adobe Pro (since I don't have the original on my laptop). It will be merged with the isotopes PR #307. Will do similar for CICE.