Long term enhancement - get away from HDF5 for storage

[ianepreston]

See issue #15
HDF5 seemed like a cool storage solution when I was developing this, and it's still pretty handy. I think a SQL backend might be more useful though, and it seems like it'll resolve issues with saving data to cloud storage platforms. It'd also open up the ability to query the data using other tools, and just using python for retrieval