Trinus E3Dv6 (Bowden) Precision Piezo

This is the first public version of my Trinus print head using an E3Dv6 (Bowden) with integrated [Precision Piezo](http://www.precisionpiezo.co.uk/ "Precision Piezo") Z probe.

The design (style) has been based on the Ormerod E3D Precision piezo by Dignitate but due to the strange layout and offset of the Trinus print head. I started this design from scratch.

There are four parts to the design
* Back plate - designed to sit in the standard Trinus metal plate
* Hotend and Universal P