a good deal of Makefile and run-in-dosbox.sh refactoring, e.g. the
introduction of a dosfiles/ subdir in which dosbox runs, to eliminate
the need for the Forth PATH word to run tests.
Names are adapted to DOS 8.3 file names, PETSCII adaptions of core.fth
are reverted (DOS uses ASCII), the input test is disabled, since no
way was yet found to inject keystrokes into dosbox. And some tweaks
were applied to ans-shim.fth and the golden files to make the first
tests (preliminary & core) to pass.
- add first test for including an .fth file
- add generic rules to convert lowercase .fb files to .fth files
- check in the tools/echo-toupper/tolower.py files that I left out earlier
