stabilized y motor bracket with changes

I think that y-bracked needs some stabilization along the x-axis; furthermore I believe the whole prusa needs this too, this is the first modification of many need to be done. replacing several of the threaded Rods with 3/8" or 10mm while keeping the threaded rods that hold the bearings or drive the z-axis would be a step in the right direction.
this is based on the y-bracket by spacexula and integrated into the simplified prusav2 design.
Happy reprapping :)
fixed the bracket mirror was the