Double sided GT2 belt clamp for MendelMax & Prusa

I simply added belt grip on the other side. I haven't tested it yet. But I don't see why it can't work though. My printer is tied up at the moment.

Update: Tested. I tweaked the bottom teeth grooves to have better grip since the bottom layer is often squished for better adhesion. I deleted the other sizes since 5mm seems to the best for size and strength. You can tweak it to your needs. :D

Default setting:
belt_pitch = 2;
belt_width = 10;
belt_offset = 0; // Use for Prusa I2