Generalize layout engine

[negentropicdev]

Provide the ability for specifying nested layout engines, such as vertical, horizontal, grid, arbitrary, etc.

Another idea that was presented was creating embeddable panels with alternating splitters and panels to facilitate user resizable panes. One panel with horizontal splitters and another with vertical splitters that can be composited to create the grid as necessary. Each could be associated with a layout engine instance specific to that type to compose layout hierarchies similar to web/Qt/other frameworks.