columns: add separate wrapping config for stacked mode
columns: add separate wrapping config for stacked mode

When windows are stacked, I want cmd_up/down to wrap.  When they
are not stacked, I want them to stop at top/bottom.  Provide a
separate config.  The default is True so that the defaults are
unchanged.

Signed-off-by: Serge Hallyn <74c41eb4256ebdefae134df89af11841313d9a25@cisco.com>

tych0/qtile,qtile/qtile,ramnes/qtile,ramnes/qtile,tych0/qtile,qtile/qtile