Custom separators in the icon grid, or empty grid slots

[wduda]

An old feature request was for separators in the icon grid, or allowing blank slots to create groups, or to have so to speak line breaks after a series of icons.

The latter would look like (where Q is a Quickslot and the window is five quickslots wide):

QQQQQ
QQ
QQQ
QQQQQ
QQ