Daniel Wong

I noticed that in `sfm_test.py`, calls to `compute_fundamental()` and `compute_fundamental_normalized()` have their input variables reversed (x2 then x, instead of x then x2): `E = sfm.compute_fundamental(self.x2[:, :8], self.x[:, :8])` `E...

Improve "unknown command" error message

5

## Note I'm not sure if you want to accept this PR at this time, as the error message I've added might be out of date soon [according to this...