#7 Allow closing of Blog Items window.

[Hiram van der Gaag]

For some reason, the Blog Items window cannot be closed. Having it
open all the time is not at all necessary; user can make a new document,
edit and save it, publish everything using the menu command or a key
stroke -- without ever having to consult or otherwise use the Blog Items
window.

Generally speaking, restricting the user's freedom to close any window
she wants is a bad idea, but there is also another reason for wanting to
be able to close this particular window. Having it open may cause the
strange slowness in opening and saving documents that I described
earlier in two bug successive reports.