Add and document g_mount_is_shadowed plus calls to set/unset a mount as

Add and document g_mount_is_shadowed plus calls to set/unset a mount as

2008-12-01  Alexander Larsson  <alexl@redhat.com>

        * gio.symbols:
        * gmount.[ch]:
        * gunionvolumemonitor.c:
        * gvolume.c:
	Add and document g_mount_is_shadowed plus calls
	to set/unset a mount as shadowed

svn path=/trunk/; revision=7716