Issues with byte strings in ASCII table output

When writing the following table to an ASCII file in Python 3:

```
from astropy.table import Table
table = Table.read('http://mpia.de/~robitaille/astropy/test.vot')
table.write('test.txt', format='ascii.fixed_width')
```

The output is:

```

|    Prog |        Name |           Obs |   tos |   Type |    Vel | n_Vel |   Flow | n_Flow |  Fhigh | n_Fhigh |   Conf |        RAJ2000 |        DEJ2000 |
| b'N032' | b'AFGL2591' | b'2003-12-06' | 16800 | b'MAP' |   -5.5 |  b'L' |  80578 |   b'L' | 203407 |    b'L' | b'6Cp' | b'20:29:24.87' | b'+40:11:19.8' |
| b'N032' | b'AFGL2591' | b'2004-05-15' |  1140 | b'MAP' |   -5.5 |  b'L' |  80578 |   b'L' | 203407 |    b'L' | b'6Dp' | b'20:29:24.87' | b'+40:11:19.8' |
| b'N032' | b'AFGL2591' | b'2004-05-15' |  7740 | b'MAP' |   -5.5 |  b'L' |  80578 |   b'L' | 203407 |    b'L' | b'6Dp' | b'20:29:24.87' | b'+40:11:19.8' |
| b'N032' | b'AFGL2591' | b'2004-05-16' | 24060 | b'MAP' |   -5.5 |  b'L' |  80578 |   b'L' | 203407 |    b'L' | b'6Dp' | b'20:29:24.87' | b'+40:11:19.8' |
| b'N032' | b'AFGL2591' | b'2004-05-17' |  3060 | b'MAP' |   -5.5 |  b'L' |  80578 |   b'L' | 203407 |    b'L' | b'6Dp' | b'20:29:24.87' | b'+40:11:19.8' |
| b'PB3F' | b'AFGL2591' | b'2005-12-25' |  4050 | b'MAP' |    0.0 |  b'L' |  86610 |   b'L' | 230538 |    b'L' | b'6Cq' | b'20:29:24.80' | b'+40:11:19.0' |
| b'PB3F' | b'AFGL2591' | b'2005-12-26' |  4050 | b'MAP' |    0.0 |  b'L' |  86610 |   b'L' | 230538 |    b'L' | b'6Cq' | b'20:29:24.80' | b'+40:11:19.0' |
| b'P04A' | b'AFGL2591' | b'2006-02-03' |  9000 | b'MAP' |   -5.5 |  b'L' |  80578 |   b'L' | 203407 |    b'L' | b'6Aq' | b'20:29:24.87' | b'+40:11:19.5' |
| b'PB3F' | b'AFGL2591' | b'2006-06-03' |   675 | b'MAP' |    0.0 |  b'L' |  86610 |   b'L' | 230538 |    b'L' | b'5Dq' | b'20:29:24.80' | b'+40:11:19.0' |
| b'PB3F' | b'AFGL2591' | b'2006-06-04' |  7425 | b'MAP' |    0.0 |  b'L' |  86610 |   b'L' | 230538 |    b'L' | b'5Dq' | b'20:29:24.80' | b'+40:11:19.0' |
| b'PB4A' | b'AFGL2591' | b'2007-02-19' |  9450 | b'MAP' |   -5.5 |  b'L' |  80126 |   b'L' |  81030 |    b'L' | b'6Aq' | b'20:29:24.87' | b'+40:11:19.5' |
| b'PA4A' | b'AFGL2591' | b'2007-03-04' | 10800 | b'MAP' |   -5.5 |  b'L' | 203055 |   b'L' | 203739 |    b'L' | b'6Aq' | b'20:29:24.87' | b'+40:11:19.5' |
| b'PA4A' | b'AFGL2591' | b'2007-03-13' | 10935 | b'MAP' |   -5.5 |  b'L' | 203055 |   b'L' | 203739 |    b'L' | b'6Bq' | b'20:29:24.87' | b'+40:11:19.5' |
| b'PA4A' | b'AFGL2591' | b'2007-03-15' |  9450 | b'MAP' |   -5.5 |  b'L' | 203055 |   b'L' | 203739 |    b'L' | b'6Bq' | b'20:29:24.87' | b'+40:11:19.5' |
```

but I think the writers need to be smarter and not show the ``b'...'``.