Convert the "EURO support" preference over to gconf.

[David Hampton]

Log Message:
-----------
Convert the "EURO support" preference over to gconf.

Tags:
----
gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/app-utils:
        prefs.scm
    gnucash/src/core-utils:
        gnc-gconf-utils.h
    gnucash/src/gnome:
        gnc-plugin-page-account-tree.c
        gnc-split-reg.c
    gnucash/src/gnome/schemas:
        apps_gnucash_general.schemas
    gnucash/src/gnome-utils:
        preferences.glade

Added Files:
-----------
    gnucash/doc:
        What_is_Euro_support