#7: Refactoring a bunch of stuff with layouts and positions and sizing.
Currently, dimension-independent layouts (e.g. ones that you can switch
the major axis on or flip them) are very difficult to write due to all
the conditionals required (e.g. size=isVertical ? getHeight() :
getWidth()).  Want to make this much easier, e.g. getSize(Orientation).
Just got started, put some ideas in code.  Old button demo should work
again but haven't tested.