Add proper support for height-for-width elements (or WFH) such as Text element

In general, Text elements with wordWrap is badly supported by layouts (or rather, the layouts support it, but Text does not provide the info that the layouts need - a height-for-width function). Basically, Text elements with word wrapping will update their implicitHeight when an explicit width is set on them. This works for Text elements alone, but its not ideal for layouts. The problem is that Text elements assumes that the geometry (width) has to be applied first in order to get a sensible implicitHeight. This is the opposite of how layouts work, as they gather implicit sizes first, and then ultimately applies the geometries.