[m-dev.] timetable for deleting the parts of options.m that are being replaced

[Zoltan Somogyi]

Normally, when we construct a replacement for some functionality,
we keep the old one around for a week or two in a sort-of standby mode,
ready to switch back to it if we detect some problem with the new version.

This technique does not apply to my changes to options.m, for these reasons:

First: because neither we nor other users of Mercury usually *use* the help system
on a daily basis, and so there is no is reason to think that regular usage
would reveal any problems that exist.

Second: any issues would NOT stop anyone from doing their work, since
user_guide.texi would remain unchanged for a while. (I plan to update its
invocation section using an automatically-generated, texinfo-specific version
of the output mmc --help, once everthing else in options.m is finalized.)
This makes it ok to fix any issues in the new system *without* falling back
to the old one for the duration of the fix.

Unless you guys request otherwise, I intend to delete the parts of options.m
that are not needed in the new system in about 48 hours. I want to do this
because rearranging the order of optdb clauses to match the chapter structure
in print_help.m would be significantly harder to do if I have to constantly
step around optdef clauses, which are scheduled to be deleted soon anyway.

Zoltan.