feeder for "Ultimaker 2 Rail System"

reinforced version of my previous feeder, adapted for use with the "Ultimaker2 Rail System".
After hundreds of printing hours on my feeder the hook got a little loose, so I decided not just to replace it but also to strengthen it a little. Since using the U2RS means you don't have the size restrictions you would have at the backplate, I added a few millimeters here and there, and merged the body with a mounting plate. Also modified the hook shape a little to have more surface area touching the