Now that all logics formally bared by 'colorui' have been moved to the main ui
class, that class is empty and can be dropped. As a nice side effect we can get
rid of the baroque Initialization associated to it.
There was much rejoicing.
This allows us to write doctests depending on a ui object, but not on global
configs.
ui.load() is a class method so we can do wsgiui.load(). All ui() calls but
for doctests are replaced with ui.load(). Some of them could be changed to
not load configs later.
since it's possible to reuse the ui object (see 6772a32edec7)
between dispatch calls, the ui might have been wrapped already.
we could probably move this test up a bit but leaving it here
allows updates to take effect by extstyles() and configstyles().
Without this fix, any calls to write_err would go to stdout instead of
stderr, and calls during pushbuffer would cause unpack ValueErrors on
popbuffer.
