Update last-changed date.
Tweak the readme.
Forgot to update the sty after changing dates
Some clean-up in runner-brainfuck.dtx
Add output-encoding key.  Also add the code for output-rescan.
Cf previous commit: output-encoding and output-rescan
Move some doc around.
Get the interpreter to ABORT" on errors.
Only bound check once for multi-pops.
Use str_set_convert on clists rather than converting chars 1 by 1.
Minor changes, comment to remind me to add the "use" key.
Towards using less native strings.  Misc cleanup.
Reorganize some code
Remove separation between Core/Double/... words.  Fix a few bugs.
Add key 'use', rename 'output-rescan' to 'rescan'.
Remove an unused macro.
Fix DO loops (nesting, negative increment, folding mod 2^{24}).
Add 'make test' rule
EVALUATE starts reading right away, not at next interpreter call.
DOES> now overrides any previous DOES> on the same CREATEd variable.