Unclear Menu navigation with Import as sub-menu

[MichaelH]

With changeset:3769, Import moved to a sub-menu of Manage, but when you select an Import option such as Greymatter, your current menu navigation status is lost--that is, it just displays the Dashboard, Write, Manage etc options with no indication you are under the Manage, Import menu.

As a note, the new WordPress export and import is working for me. Nice job Matt.

fix parent_file for imports

Attached patch highlights Manage menu when you are on an import page. The original method didn't highlight "Import" as the submenu item, so I left it unhighlighted, but this can be changed easily.

highlights Manage menu & Import submenu

Second patch highlights the Import submenu also. The devs can commit whichever one they deem correct.