Rubbers sharing the same properties should share the same mesh.

[Pandelii]

If the base properties that define a rubber are the same as another rubber they should share the same mesh. If the only difference is the transform (height above table, rotation etc) they should share the same mesh.

[freezy]

Rubbers are mainly defined through their drag points, which are in global space, so it's going to be difficult to identify duplicates. I'll keep this open though but it's quite similar to #230.