Avoid a test failure on SBCL/Windows
Fix test-utilities: EQUALP doesn't actually descend into pathnames. Use namestrings.
Patch to enforce system naming conventions.

Insist on lower-case system names, with only the characters accetpable
in logical pathnames and the forward slash, "/", which is meaningful to
ASDF.
Bump version to 3.1.0.74
Extend DEF-TEST-SYSTEM to permit systems named with strings.
Check to ensure systems have lower-case names.
Add test for system name checks.
Bump version to 3.1.0.75
Some fixes to CLISP on Windows: use ext:probe-pathname, not posix:file-stat;
use ext:run-program, not ext:shell.
Bump version to 3.1.0.76