Avoid a bug with old smart-serial firmware versions.

Signed-off-by: Andy <andy@bodgesoc.org>
Signed-off-by: Chris Morley <chrisinnanaimo@hotmail.com>
gscreen - fix preferece file option saving bug

if you getpref an option more the once, it would error often silently
but use the default value. Set it up to use raw parser instead of
interpeter - little idea what was really wrong. on ethe second
run if would try to check the value for substituion
if "%(" in value:
which cannot be in a Float value!
gscreen -fix dialogs to not affect fullscreen

popping dialogs in fullscreen makes the menubar show.
setting the dialog window from toplevel to popup fixes this.
just gotta figure out how to do that for hal_filechooser
gscreen -add a button to launch halscope