Merge #461: docs: remove unneeded copyright document

8a49a94 docs: remove duplicate COPYRIGHT file (Cameron Garnham)

Pull request description:

ACKs for top commit:
  da2ce7:
    ACK 8a49a94

Tree-SHA512: 1f61d592ac99559b571f4c3ab0ef85ae349364b47450ebf0cdd252582de6dd2ade78970d5cc3bafb71cdccf8cc01b6eb93591268c8fd86bbbbfb42a1c0721037

Author: da2ce7