USB tidy - parameterised.

I designed a USB tidy while awaiting delivery of my Ulitmaker. This is a significant revision of that design as I am a little more knowledgeable about the 3D printing process now.
The idea was to make the bewildering array of USB to something or other cables I've somehow accumulated easy to store and find when needed.
The design is very nearly fully paramterised. Certainly it is easy to vary the number of 'slots'.