3.10 support and add 3.9 bytecode testing, rework version testing

[rocky]

WIth 3.10, it is no longer tenable to use floating point numbers as versions. (This was noticed a while ago, but it was a pain to fix until now when it absolutely necessary).

Also:

• Add in 3.10 opcodes.
• Add 3.9 and 3.10 bytecode tests
• Start testing on 3.9 and 3.10 and pyston

FIxes #84