MK2.5 Bear BMG Extruder X-Carriage

No one else has done it, so it fell to me to make this happen. Hopefully it works out. It has not currently been tested but I will test it soon. The MK3 version works and this was just me adding the x-axis end-stop arm to that, which in theory is all that was needed to adapt the design to the MK2.5.