Simplified E3D V6 compatible X carriage for 3Dtje Mini 3D Printer- Remixed with endstop support

As I don't own stepper drivers that are fancy enough to run without endstops, I've modified part of fiveseven808's improved 3dtje x carriage to incorporate a x-carriage screw (specifically an M3x20) provision, thus (hopefully) allowing an X-axis endstop to be used (the positioning of the screw is based on that on the original 3dtje design, albeit only roughly). The new part works with the original "hotend_v2_cut_standalone.stl" provided in fiveseven808's design, and replaces the second half of t