New dialog to export the Chart of Accounts to QSF XML.

[Neil Williams]

Log Message:
-----------
New dialog to export the Chart of Accounts to QSF XML.
Enable import of QSF XML.
Fix QSF backend object count and validation; add to KVP read support.
Fix char bug in qof_book_merge.

Tags:
----
gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
        HACKING
    gnucash/src/app-file:
        gnc-file.c
    gnucash/src/backend/file:
        gnc-backend-file.c
    gnucash/src/backend/qsf:
        qsf-backend.c
        qsf-xml.c
    gnucash/src/engine:
        qof_book_merge.c
        qofbackend.h
        qofsession.c
        qofsession.h
    gnucash/src/gnome:
        Makefile.am
        druid-merge.c
        druid-merge.h
        gnc-main-window.c
        gnc-plugin-page-account-tree.c
        window-main.c
    gnucash/src/gnome/glade:
        Makefile.am
    gnucash/src/gnome/ui:
        gnc-main-window-ui.xml

Added Files:
-----------
    gnucash/src/gnome:
        dialog-chart-export.c
        dialog-chart-export.h
    gnucash/src/gnome/glade:
        chart-export.glade