Table join does not work with multidimensional columns

Discovered as part of https://github.com/astropy/astropy-benchmarks/pull/10

```
import numpy as np
from astropy.table import Table, join

t1 = Table()
t1['a'] = [1,2,3]
t1['b'] = np.zeros((3,4))

t2 = Table()
t2['a'] = [1,2,3]
t2['c'] = [4,5,6]

join(t1, t2)
```

gives

```
Traceback (most recent call last):
  File "bug_table.py", line 12, in <module>
    join(t1, t2)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/astropy-1.0.dev9932-py3.4-macosx-10.8-x86_64.egg/astropy/table/operations.py", line 149, in join
    uniq_col_name, table_names, col_name_map)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/astropy-1.0.dev9932-py3.4-macosx-10.8-x86_64.egg/astropy/table/np_utils.py", line 280, in join
    out[out_name] = array[name].take(array_out)
ValueError: could not broadcast input array from shape (3) into shape (3,4)
```

cc @taldcroft