6.0.0
Reworked for Python 3.10.
We had been internally using floating point numbers for version testing.
Clearl this doesn't work to distinguish 3.1 from 3.10.
(This was a flaw known about for a while and we'd been avoiding).
- Add 3.10 opcodes.
- Add 3.9 and 3.10 testing.
- Some tolerance for running from 3.11
- Update magic numbers
- Expanding testing to include pyston and PyPy 3.7
- Improve distribution packaging, e.g. Python 3 wheels should no longer be attmpted on Python 2.x