3Dtje stronger 3.1-024_lever

My lever broke off. It wouldn't push the rolling wheel to the motor, didn't feed filament so couldn't print anymore. Luckily I had an old spare one. Since that one was the wrong color, I decided to print a new one. But to avoid the same part breaking at the same place, I made some (very small) enhancements to make it a bit stronger.

Basis of this version was the original 3.1-024_lever.stl. Using SketchUp I removed all triangle lines from the flat surfaces to make it easier to change. Then I a