Upgrade for Spool Holder

This two things are for the T_B_A Spool Holder with Bearings.
I have made:
- Spool Holder Spacers.stl is a small piece to put under the bearing axis to move up it. This because some spools, like my geeetech, has a gap between the innser deameter and the innes side of the spool. This piece move up the axis of the bearing but it stay in place.
Print 4 of this.

- Spool holder Adapter.stl make a flat surface between spool inner diameter and the bearings. This make more easy and fluid the spool rotation on bearings.

Thanks to T_B_A for the agreement to remix his thing.