modified PRUSA i3 mk2 half mod BEAR upgrade

Just another PRUSA upgrade clone to stronger frame.

I modified the BEAR mod because I didn't get precutted v-slot extrusion. Instead of I choose the I-type and modified the parts to fit. I also added some extra parts (for example a modified PSU case, another y-belt holder and some caps/feet).

I also added a dual USB-socket in the PSU.

Still waiting for the MK2.5 upgrade for a better heatbed and extruder.

All credits going to pekcitron, MartinMajewski and fiveangle.