Avoid three-scrollbar situation in Acq -> Providers -> Invoices tab

Avoid three-scrollbar situation in Acq -> Providers -> Invoices tab

You can certainly still get two scrollbars here, which is unfortunate,
but at least you shouldn't be able to get three anymore.

This solution also gives us a way to deal with the same problem if/when
it is seen in other interfaces (I feel like I've seen it occasionally).

Before now, AutoGrid created a content pane dynamically and placed
place it in the DOM before its own root DOM node.  Depending on where
that lands in a surrounding hierarchy of dijit.layout.ContentPane
objects, that can create a situation where more scrollbars are generated
to show more DOM objects in a limited space.  This generated content
pane is where AutoGrid puts its Back, Next and potentially Filter links.

Now you can specify a DOM node where you want that material to go
instead, and control the layout better.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>