UI:

UI:
* Don't call generic layout hints templates anymore, i.e.
  TemplateRow becomes Row, etc.
* Added more general layout nesting, using uiLayoutSplit()
  and uiLayoutBox() functions, for which the sublayouts
  can then be accessed using uiLayoutSub(), to put items
  in those sublayouts.
* Some steps to make the layout decisions, like which items
  to put in which columns, independent of the width of the
  window or the text in the buttons. We want the layout to
  be stable under resizes and translations.
* Added an "expand" parameter to uiItemR, used now to expand
  enums into a row instead of using a menu.