[WIP] Feature/csv to sql natively

When finished, this PR should address #352. New `into` function calls out to to native COPY function of various DBs.  Has optional `if_exists` argument (similar to pandas) to handle three cases: replace, append, and fail

```python
into(sql,csv, if_exists="replace")
```


<!---
@huboard:{"order":342.75,"milestone_order":454,"custom_state":""}
-->

I was advocating with for both (or generally just any system that could be extended to other ways of writing this down) but don't have very strong opinions on the topic.  

But most of this desire comes about because it would be nice to see parameters that were closer to other Python idioms established by csv and pandas.  So if those are hit I don't care too much otherwise.