[WIP] Reorg Docs

Going through the docs, updating things to match the reorg branch

I haven't even done spell check yet.  Be merciful.

Fixes #329
Works fine in IPython.  How are you executing your code?  I can change it if you like. 

```Python

In [1]: from blaze.data.csv import CSV

In [2]:  >>> csv = CSV('accounts.csv', mode='a')

In [3]: >>> csv.extend([(6, 'Frank', 600),
   ...: ...             (7, 'Georgina', 700)])
```