SPM08 thompson linear bearings mod for i3 EiNSTeiN variant X-ends JBFromOZ remix

Further refinement of the X-ends to suit Thompson 4 part linear bearings.
Anyone who has attempted to use Thompson SPM08 linear bearings in place of LM8UU's will know that they are close, but painfully not close enough to LM8UU to be used in place.
I have modded these X-ends to suit the Thompson SPM08 linear bearings (slide like smooth buttery goodness.)
I have included the 608 skate bearing cheek mod, and have also fixed a recently detected issue with the "Friction Fit" on 8mm smooth rod