Convert the default currency preferences over to gconf.

[David Hampton]

Log Message:
-----------
Convert the default currency preferences over to gconf.

Tags:
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gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/app-utils:
        global-options.c
        prefs.scm
    gnucash/src/gnome/schemas:
        apps_gnucash_general.schemas
    gnucash/src/gnome-utils:
        dialog-preferences.c
        preferences.glade