Better w+h for context max vals & favour max vals.
Better w+h for context max vals & favour max vals.

'get_width' and 'get_height' can tell you the current width+height of
the canvas, 'get_defined' can tell you what the canvas started out as
(by configuration or just chance), but max_width and max_height tell
you what the canvas _could be_.

When adding/removing/resizing it for controller components, it turns
out, you almost always want to know the biggest it can possibly get.

I can imagine an intentionally-smaller canvas getting blown up by
this -- there are more flexible and abstract things I can imagine,
like having a "type" for the "defined" data, eg "fixed" vs "flex",
where "fixed" means "always use the defined data" and "flex" allows
some strings like "max" or "min", which will behave more like the
code currently does. I'll look at writing that when I need it. :)

wcarss/creek,wcarss/creek