Blender Git Loki

A few Mesh fixes:
* edge and face extend() methods now add edges and faces in the order given
by their parameters. Note that if duplicate edges or faces are specified,
the order is preserved but the dups are removed, so indices won't match.
* allow extend(), findEdges() and faces.uv to accept lists or tuples
* fix bug in mesh.verts.extend() which didn't correctly check argument types