hephestos improvements big pack

this is a collection of the most interesting parts that I have made for BQ hephestos.
it includes:
- fan mount
- z axis bracket with 625zz bearings
- frame stabilizer that fixes vibrations and gives more stiffness. I used 2 M8 rods 42 cm long
- new and improved version of lm8uu supports for y axis

if you print some parts, post a pic.
thanks