Parametric n-way (0-6 way) pipe fitting

I couldn't find exactly what I was looking for in the other available models, so I pulled this one together in OpenSCAD.    You can also use the Makerbot Customizer over on thingiverse: https://www.thingiverse.com/thing:6302108

This is completely adjustable, including the number of fittings, sizes and lengths of the fittings.  

Make your adjustments, export your STL and print - watch the orientation and use supports when your model has unsupported pipe fittings.    

Leave yourself a bit of extra space to compensate for your printer's accuracy and for the fact that hollow cylinders are hard to print perfectly round

Special points for anybody who can upload a print of a 0-way fitting  :-)

v1.0 - initial release
v2.0 - fixed code to use diameter vs radius. 

v3.0 - completely redid the code to be n-way with lots of parameters

v3.1 - fixed a code bug that cut the holes even if the joint was disabled.