3030 extrusion profile clips

**Updates**:
-Dec 21th 2014: Add a 3rd version of the clip with longer termination that go up to the end of the 30mm extrusion. It can be usefull when 2 sets of cables are going into 2 different extrusion holes.

You will find 2 types of clips here:
-Extrusion_Clip.stl is a simple clip (10mm height) compatible with 3030 extrusion profiles.
-Extrusion_Clip_2.stl is a modified clip with a guide that fit inside the hole of the extrusion profiles. It's also 10mm high.
-Extrusion_Clip_3.stl