gEDA-user: [pcb] settings file

[DJ Delorie]

I just added code to use a common text file for settings (instead of
relying on ~/.Xdefaults for lesstif, gnome-config for gtk, etc,
although those still work too).

Settings are looked for in:

$prefix/share/pcb/settings
$HOME/.pcb/settings
./pcb.settings

There's a :SaveSettings() action, which optionally takes a "local"
argument (:SaveSettings(local)).  It saves the settings in
~/.pcb/settings (non-local) or ./pcb.settings (local), where settings
which still have their built-in value are listed as commented out (so
you can see what the settings are, but they won't override new
built-in defaults).

Also, significantly, the ./pcb.settings file acts like gafrc in that
it can override the footprint paths (and other settings) on a
per-project basis.