This should be suitable for laying out text objects with word-wrap,
where each view is a "word" or break between "words". This should be
useful for any other objects that could benefit from similar layout
rules. All eight flows are supported left-right-top-down (English and
most European languages), right-left-top-down (Arabic and similar),
top-down-right-left (Chinese, Japanese, Korean), top-down-left-right,
as well as bottom-up variants of those four.
More work is needed for support of things like views being centered on
the flow line rather than on one edge (depends on flow direction),
offset views, and others. Suppression of "spaces" at the beginning of a
line is supported but not tested.
