Enh/hdf5 (mostly) everything

This is a merge/combination of earlier hdf5 branches. This is ready for review.

Note: the storage situation is terrible (files are huge and will balloon with consecutive writes), but could be dramatically improved pretty easily by simply enabling compression. It's probably best to wait until a pytables 3.x package lands in canopy because the API differences between 2.4 and 3.x start to matter here and the 2.4 docs don't seem to be not available online. It would be a poor use of time to chase down the old api if 3.x is going to be available soon.