oox: introduce W_TOKEN() macro

It was inconsistent that when parsing <a:foo> elements, A_TOKEN(foo) was
available, but for <w:foo> elements there was no W_TOKEN() macro.

Also, there were two manual variants (NMSP_doc|XML_foo or via
OOX_TOKEN(doc, foo)), replace both of them with W_TOKEN() for easier
searching.

Change-Id: Ic5cd027f07518535b92671ffe3c486016a3f9f0a
sw: unused includes in objectformattertxtfrm

Change-Id: Ib564b09ddf68d045dcb89f1127c65aa95b3c1f68
sw: unused includes in pagechg

Change-Id: I0c50675ba5fe7ff3763c4e598cccaea823a324f9
sw: unused includes in paintfrm

Change-Id: Ie8aa47d98849d8a8fc0962f0fdf9758fad59088f