BigBox imported

["Colin Walters" <walters verbum org>]

Hi,

A quick note for developers - the BigBox class (originally written by
litl) has been imported.  This class is a very convenient way to do a
number of different kinds of layout; it has expand vs not, horizontal
and vertical orientation, padding, and in particular rounded corners.

If you want to see how it's used now a quick grep should pick up a few
places.  For example, the rounded corners in the search entry now.