HarlanH/julia — pull request #1 by tshort (2012-06-21 13:51:18+00:00)
Title: Fix for SubDataFrame ref and change to col slices for DataFrame

This includes one fix for SubDataFrame ref and the following change to column slices. Before the change, giving row indexes and one column index returned a DataFrame:

```jl
julia> d[[3,4],3]
d3
[1,] 1.2548589682498181
[2,] -0.8191829220866111
```

After the change, you just get a DataVec back. This matches R.

```jl
julia> d[[3,4],3]
[0.3726377693434697,-0.2106084457960923]
```
(That column was randomly generated, so that's why the numbers are different.)