Refactored HDF5 reader, path can now be to a group or dataset, and if no path is specified, the first table found will be read. If more than one is found, a warning is emitted.
Refactored HDF5 writer, use recursion to simplify logic
PEP8 fixes
Added HDF5 tests to ensure good coverage
Fix --coverage for Python 3.x
Added note about new behavior of selecting first table
Merge pull request #1159 from astrofrog/io/hdf5-auto-find-table

Improvements to HDF5 reader/writer