Replace copyright and license in all source and header files about openfx HOT 3 CLOSED

New file can bear new (c)

The theory from our transition research for this, as it would have otherwise required we get a signature from all who may have contributed (and their successors for those who are not alive)
Old files we edit should have 2 lines, (c) OpenFX 2003-2022
(c) new one 2022-23

from openfx.

From our perspective, only the first two lines are required...

// Copyright Contributors to the OpenFX project.
// SPDX-License-Identifier: BSD-3-Clause

Note that I removed the (c) as it's somewhat redundant. Also, adding the year really doesn't add any value, and puts an additional burden on the project to change the year on each file every year.

from openfx.

Now being implemented in #110

from openfx.