MakerBot pen holder (1 piece)

This is a pen holder for the MakerBot.

I did this new design, although there already exists at least one other pen holder design on thingiverse (http://www.thingiverse.com/thing:790).

The main difference: It's only one simple part.

There are two stl files:
- Stifthalter_1part.stl: This contains the part layed out at a 45° angle. That way it easily fits on the MakerBot build platform. This file is best printed without a raft.
- Stifthalter_1part_horizontal.stl: The same object but layed out at 90°. That way a raft would be much smaller, but the object uses almost the complete width of the build platform...