BUG: read_table error with tabs, dtype and index_col
This gist demonstrates the problem:
https://gist.github.com/brentp/6066942

It's discussed in this thread:
https://groups.google.com/forum/#!topic/pydata/hIIZpZqbY5M

As discussed in the thread, there is some interaction when specifying dtype, index_col, and sep in read_csv.

As the gist shows, things work find with sep="\s+", but fail for the same set with sep="\t" even though the file is tab-delimited.
