Convert the account tree summary bar over to using GConf preferences.

[David Hampton]

Log Message:
-----------
Convert the account tree summary bar over to using GConf preferences.

Tags:
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gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/app-utils:
        prefs.scm
    gnucash/src/gnome:
        window-main-summarybar.c
    gnucash/src/gnome/schemas:
        Makefile.am
    gnucash/src/gnome-utils:
        gnc-main-window.c
        preferences.glade
    gnucash/src/gnome-utils/ui:
        gnc-main-window-ui.xml

Added Files:
-----------
    gnucash/src/gnome/schemas:
        apps_gnucash_window_pages_account_tree.schemas