autocorres: use LICENSES directory in the release

Signed-off-by: Gerwin Klein <gerwin.klein@data61.csiro.au>

autocorres: include RISCV64 in supported architectures

Signed-off-by: Gerwin Klein <gerwin.klein@data61.csiro.au>

regression: force use of python3

Python 2 has passed its sunset date, and many distributions are
withdrawing support for Python 2.

PEP 394 recommends distributions always install versioned interpreter
commands (e.g. `python3`), but does not make a recommendation about
whether or not an unversioned command (`python`) should exist, or what
version it should run.

It therefore seems advisable to explicitly run scripts using the
`python3` command, for scripts that are compatible with Python 3.

Here, we do this for Python scripts used by `run_tests`. For this to
work, some scripts have been updated in ways that will break Python 2
compatibility. But for some other scripts which were already compatible
with both Python 2 and 3, we have not yet removed Python 2
compatibility. There are also miscellaneous scripts that are not used by
`run_tests`, and these have not yet been updated to Python 3.

Signed-off-by: Matthew Brecknell <Matthew.Brecknell@data61.csiro.au>

style: pep8 style for python files

licenses: convert license tags to SPDX

autocorres: update tools for Isabelle2019 release

autocorres: update release tool for Isabelle2018

Note that we have removed the LIB_FILES manifest and no longer intend
to maintain it manually. Instead, we just extract the entire Lib and
CLib sessions from the L4.verified repository. This means that the
next AutoCorres release will have some unneeded theories and a couple
of files with GPL licenses.

autocorres: update for version 1.4 release

autocorres: prepare packaging scripts for release 1.3

Fix up c-parser and autocorres for AutoCorres 1.2 release.

autocorres: update README and packaging scripts for release.

autocorres: Support building documentation in the release.

autocorres: Ensure license files included in releases.

autocorres: Setup release scripts for new directory structure.

Import release snapshot.