setup.exe option parsing in flux

[Christopher Faylor]

I just checked in some preliminary changes to setup.exe option parsing.
I modified it so that all saved options are now stored in a single file
"/etc/setup/settings.rc".  Options are retrieved via a UserSettings
"get" method.  As a stopgap measure, the old single-file method is used
when an option is missing from settings.rc but all parsing of this file
is limited to one function rather than in a few different places.

I haven't done exhaustive testing on this.  It seems to work ok but I'll
do more checking tomorrow.  At some point I'll add the saving of the chooser
screen geometry.  That was more-or-less what predicated this rewrite.  I
didn't like the fact that every class opened its own file and did its own
parsing of the file; I didn't want to write another parser/generator for
saving screen geometry.

Anyway, please consider setup.exe to be unstable right now.  The CVS
trunk is not ready for prime time.

cgf