Reverting potentially plagiarized code. The developer team did not sign off on this commit.

revert fix clong format

This reverts merge request !17

This formats all copyright comments according to SPDX formatting guidelines.
Additionally, this resolves the remaining GPLv2 only licensed files by relicensing them to GPLv2.0-or-later.

Silences the following warnings-turned-errors:
-Wsign-conversion
-Wunused-private-field
-Wbraced-scalar-init
-Wunused-variable

And some other errors