[MOAB-dev] In PyTAPS, how to create edge entities by pytaps?

[Huayi Wei]

Hi, there,

I loaded a tri mesh by PyTAPS. And I want to get the edge entities, but 
edge entities doesn't exist in this mesh instance. So how to create or 
get the edge entities ？

```
 >>> s = "4k-tri-plane.vtk"
 >>> mesh = iMesh.Mesh()
 >>> mesh.load(s)
 >>> mesh.getNumOfType(iBase.Type.all)
6085
 >>> mesh.getNumOfType(iBase.Type.vertex)
2085
 >>> mesh.getNumOfType(iBase.Type.face)
4000
```

Best

Huayi