Dyson v12 dovetail mount

This is a slight remix that features slightly (6.4mm) cut mount from the original model, that allows connecting the v12 accessories. It also works for standard ones. 

I also modified the dovetail cross part adding the countersunk hole for M4 screws - so it can be mounted without the rails.

My solidworks somehow can't read even step files so the changes had to be simple.

I also added version for v12 that with the rail mounted on the cabinet's ceiling (or probably sideways.