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
```
I didn't intentionally adopt it for Blaze.  @cpcloud was pretty gung ho about it, I just let things happen.  We still converse back and forth about the right amount of py.test magic to use.

I'm not convinced that the use of py.test fixtures is essential to writing good test code.  But again, maybe this is due to my own ignorance.

> Adding slight variation of a test should be very simple and not involve manually writing additional test code

I agree that good testing is important and that tests should be well designed to make this easy (otherwise developers won't bother.)  It doesn't mean that you need to use a particular framework.  By my argument above I'm actually not convinced that using pytest magic makes it easier for the majority of developers.

In this immediate conversation I'm not insisting that testing be framework free, merely that it be framework light.  I'm much more willing to accept the use of things like `importorskip` which are relatively isolated than things like full-blown fixture-magic.