amend copyright & licensing blocks
as per mailing list discussion...
I've just used "Copyright (C) 2016 The Debian Live team" here. If it is preferred that this be amended to use "2016-2020" and/or to include an email address then I am open to this.
Current versions of the project files are built upon versions published and licensed by Daniel Baumann, but are modified copies of those files and thus need to be marked as such per licensing requirements (afaik he did not pass along ownership / licensing rights to anyone when he left the project). We should also be careful to not be misrepresenting such modified copies as being attributed to Daniel.
Adding a new copyright line referring to "The Debian Live team" should suffice for this.
The authorship block in man pages has also similarly been updated.
Notes:
- tweaked a copy of daniel copyright lines stating 2014 instead of 2015. both of these cases were in files that i had personally introduced in some of my past merged commits that moved some code around. i don't know why they stated 2014.
- binary_onie was introduced in 2018, so that has a 2018 date instead of 2016 unlike the rest.
- 'efi-image' is a 3rd-party (Canonical Ltd) work that we bundle, but it has been modified by 674794a8 and 36a3ba76 so I similarly added a debian live copyright line.
- 'grub-cpmodules' is similar. it was only changed by the indentation fix of 36a3ba76 but modification is modification, and this does help cover any possible future changes that might be made.