Make `vel` a real 2D array
Make `vel` a real 2D array

It was coming out looking awkward, like:
```
[array([-0.00024867, -0.00022927, -0.00020292])
 array([  4.39395015e-05,   4.05129202e-05,   3.58554036e-05]) 0.0]
```

skyfielders/python-skyfield,skyfielders/python-skyfield