ENH: add pandas.hdfstore suppport


includes some other commits to make testing clean
- https://github.com/jreback/into/commit/82a6546ee5c6465a851601873f00ff05109a3c0c is in another PR already
- https://github.com/jreback/into/commit/836d5caaf2e3189882a53df343a18a785672c3a2 should be cherry-picked

- Added into support to include chunking / column selection / reading and writing

the use of uri's in resource that need a hierarchical disambiguation
based on priority and the raising of ``NotImplementedError`` by matches
that do not wish to be a resource for that particular uri

IOW. a higher-priority uri matches (e.g. .h5), but the data is
actually PyTables, so HDFStore 'passes' on the processing. PyTables
is next in the chain so it will then process.

Note that a uri can be more fully-disambiguated via a head element
The default is ``hdfstore`` (this only matters for writing), reading
is unambiguous.

e.g.

```
....../file.h5 -> hdfstore
hdfstore://....../file.hdf5|h5 -> hdfstore
pytables://....../file.hdf5|h5 -> pytables
h5py://........../file.hdf5|h5 -> h5py
```
yep I agree with @cpcloud . I actually seem a fair number of cases in ``into`` that really should just be in the setup code. It makes it centralized, easy to manage, and to be honest more intuitive than having each file do its own setup. That's the beauty of fixtures. You can have them recreate an exact env w/o very easily and without having the test writer even think about it.

It REALLY matters when you have resources that you want to make sure get closed, don't overlap and such. (e.g. PyTales and the like)