Filament spool / reel holder (for germanRepRap X400)

A modified Reel Holder from Opensourceclassroom.org:

- I enlarged parts to have a more stable fitting
- stretched the wheel distance to receive larger reels and more than 2kg reels
-strengthened the construction

You can mount it on the top the printer:
- have more space on the table
- add several of them to quickly change filament