For the spec, see https://reuse.software/spec/

This adds copies of all licenses used by any file in the git repository to
the LICENSES directory, and adds a DEP5 file containing the licenses and
copyrights of the debugger scripts (which don't support inline comment
headers) and the documentation files (most of which came from the wiki
previously, and so were not contributed under the dual MIT/LGPL license of
the repo.)

LICENSES are excluded from spell checking since they are legal documents
included as-is.