Add a new dialog to reset the state of warning messages.

[David Hampton]

Log Message:
-----------
Add a new dialog to reset the state of warning messages.

Tags:
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gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/gnome/schemas:
        apps_gnucash_dialog_common.schemas
    gnucash/src/gnome-utils:
        Makefile.am
        gnc-main-window.c
    gnucash/src/gnome-utils/ui:
        gnc-main-window-ui.xml

Added Files:
-----------
    gnucash/src/gnome-utils:
        dialog-reset-warnings.c
        dialog-reset-warnings.glade
        dialog-reset-warnings.h