Commit 3a3c889b (2 years ago now) changed loadfiles() to use liberal file
matching (e.g. "syncterm.exe" matched both "syncterm.exe" and
"syncterm_v1.2b.exe").

This could produce surprising results when doing file list querieis/operations
with the FileBase methods via JS (e.g. jsexec utils) and (now that I look at
it), the FTP server too.

So we should not have been doing liberal file matching *everywhere* loadfiles
is used, just where it was a usability issue (due to displayed filenames being
truncated to 12 chars for <=80 column terminals).

Now solved by add/use of new liberal_filepattern() function only in the
built-in file listing methods: sbbs_t::listfiles() and sbbs_t::listfileinfo().

Note: Custom JS file searching/listing scripts may now need their own
work-arounds for this usability issue, if they have it.