[Ohrrpgce] SVN: teeemcee/12968 physpeak: merge changes from Lenny, especially constant folding optimisa

[subversion at HamsterRepublic.com]

teeemcee
2022-05-17 07:49:21 -0700 (Tue, 17 May 2022)
418
physpeak: merge changes from Lenny, especially constant folding optimisation

This includes some changes from two years ago which I hadn't merged.

Also:
-major changes to hsfile.py whereby the .hs lumps are kept in memory rather than
 stored as temp files
-various code cleanup
-better solution to circular imports by adding AST_build to parser.py
 (differs from Lenny's solution)

"return" arg is no longer optional.
---
U   wip/physpeak/hsc.py
U   wip/physpeak/hsi.py
U   wip/physpeak/hslib/ast.py
U   wip/physpeak/hslib/gen.py
U   wip/physpeak/hslib/hsfile.py
U   wip/physpeak/hslib/parser.py
U   wip/physpeak/hslib/parser_utils.py
U   wip/physpeak/hslib/post.py
U   wip/physpeak/hslib/tld.py