Anti-Backlash platform for Linear slide XY

This is a remixed part for citrofan's excelent linear slide for XY table (http://www.thingiverse.com/thing:898212).

I redesigned the slider itself to add an anti-backlash system. This is for the linear bearing version (LM8UU), not the bushing version.

To assemble, you need two M8 nuts and a spring, and of course 4 x LM8UU.