ContinuumIO/blaze — pull request #447 by mrocklin (2014-08-05 19:56:38+00:00)
Title: bcolz, blz, and chunks

This creates a decent out-of-core dataframe using `bcolz/blz` and a chunking mechanism.

Along the way we've added the following pieces

* PyTables backend
* BLZ/BColz backends (see note on relation below)
* Chunking meta backend
* `chunks` dispatched function

### Example

```Python
In [2]: from blaze import *
In [3]: import h5py
In [4]: import bcolz
```
Get out HDF5 file using `h5py`, migrate to `bcolz`
```Python
In [5]: dset = h5py.File('/home/mrocklin/data/bitcoin/data-code/btc.hdf5')['/user_edges']

In [6]: b = into(bcolz.ctable, dset, rootdir='/home/mrocklin/data/bitcoin/data-code/btc.bcolz')
In [7]: b
Out[7]:
ctable((37450461,), [('transaction', '