Action, Editor performance, UX, Generic client query parameter, Whitelabel

* Renamed action nxs_login_popup_top to nxs_authentication_popup_top
* Performance; the editor now shows top menu when ready occurs instead
of when load occurs; way faster.
* UX; when dragging rows from menu to the page, the system takes into
consideration the space allocated by scaffolding rows allocated ABOVE
1/4 of the viewport. Especially for longer pages this is way more
convenient since user is not likely to have to scroll to drop the row in
place.
* Each request now delivers client query parameters. This enables
widgets to take advantage of the query parameters when redrawing rows
client side in real time. Widgets like the searchresults use it.
* Whitelabel; the logout popup also uses the icon shown on the login box
to brand the product.