makerbot replicator print head ribbon-clip

* left and right clips broke off the original
* reverse engineered:
- made clips a bit thicker
- removed holes near the clips

ribbon is really tight which makes it not so easy to re-assamble it.
to do so:
* remove top case of printer - or lift it up until you reach to gears of motors
* remove the gear of one motor - take car not to get ribbon out of place too much
* fix print head ribbon clip to both ribbon ends
* put ribbon around gear and with some force push gear ba