Bug with Table sorting?

If I try and read in the following file:

http://www.mpia.de/~robitaille/python/rosat.vot

and sort according to the counts:

```
In [1]: from astropy.table import Table

In [2]: t = Table.read('rosat.vot')

In [3]: t.keep_columns(['RAJ2000', 'DEJ2000', 'Count'])

In [4]: t.sort('Count')
```

I get some weird results:

* ``print(t)`` shows an unsorted table:

```
In [5]: print(t)
 RAJ2000   DEJ2000    Count  
--------- --------- ---------
  0.00000 -39.48403      0.13
  0.02917   8.28153      0.19
  0.04167 -63.59528      0.19
  0.04958   5.38833      0.26
  0.05250   1.77250     0.081
  0.05625  57.94125      0.12
  0.08125 -26.17556      0.12
  0.14792 -28.09819     0.072
  0.16000  79.67694       0.1
  0.17708  62.17611      0.16
  0.18417 -26.08931      0.12
  0.18583 -25.84181      0.05
```

* ``t.more()`` shows a sorted table:

```
In [7]: t.more()

 RAJ2000   DEJ2000    Count  
--------- --------- ---------
  2.24333 -23.88486      0.05
  7.83833  30.26611      0.05
 17.45833  19.65736      0.05
 20.64042 -22.90139      0.05
 36.40958  37.54028      0.05
 39.69792  40.18306      0.05
 64.73541  13.23681      0.05
 82.30708  -6.25097      0.05
 93.72875 -60.65736      0.05
 97.19500 -68.13250      0.05
107.63583  -8.70889      0.05
110.80459  58.69194      0.05
125.11417 -22.92417      0.05
```

* ``t['Count']`` shows an unsorted column:

```
In [8]: t['Count']
Out[8]: 
<MaskedColumn name='Count' units='ct / (s)' format='%9.2g' description='? Source countrate (4)'>
masked_array(data = [0.13099999725818634 0.18700000643730164 0.1899999976158142 ...,
 0.06639999896287918 0.05249999836087227 0.11500000208616257],
             mask = [False False False ..., False False False],
       fill_value = 1e+20)
```

Not sure what's going on! Any ideas?