Parametric Modular Hose Library v0.2

A busy few hours after my first attempt at a useful OpenSCAD design (http://www.thingiverse.com/thing:9446) and I've totally re-written and refactored the code into a parametric part library. It's still early days, but it already contains the basic building blocks and a bunch of basic parts (segments, nozzles, base plate).

There is also a demo section in the library that will generate a full set of example parts. Or you can un-comment the lines at the bottom to render individual parts and export the STL.

Module Structure
Basic building blocks are defined as chainable modules, taking at least one common parameter - the bore of the hose. Thus alternate hose sizes are trivial to generate (1/4 inch, 1/2 inch, etc).

Global Variables
- tolerance = controls the distance between the ball and socket surfaces
- definition = this defines the number of facets for curved surfaces (sets the $fn parameter)

Parts in the Library
- Hose segment
- Extended hose segment (user defined l