Prusa i3 MK2-X Remix with i3 MK3 features

Inspired by davtr's Prusa i3 MK2-X, and by Tom Sanladerer's review of the Prusa i3 Mk3 I set about building my own printer from scratch using as many features from the i3 Mk3 as I could. So here it is. Principle features are :-
* Trinamic TMC2130 drivers which offer advantages of
+ Very quiet operation
+ No end stop switches required. The drivers sense when a limit is reached.
+ No potentiometer adjustments. Currents are software selectable.
+ 256 microsteps.
* Prusa i3 Mk3 parts used